PDA

View Full Version : Lathe build underway: Part 1, the spindle



Evan
01-01-2009, 02:20 PM
I am starting a new machine project. My South bend is a very capable lathe but it lacks one thing that often presents a problem. It doesn't have enough swing. It isn't often that I run into jobs that are too long but swing is often a limiting factor. So, I am building a lathe that will solve that problem.

Rough specs are about 16" swing, 18" between centers, strong as hell and rigid, all steel and cast iron. Maybe 2 to 3 horsepower and a large and solid carriage with very long cross travel. No CNC at present and no threading. Electric drives using servos with feedback for speed control so computer control is easily arranged.

This isn't going to be a showpiece build, just a very functional machine that I am putting together entirely from materials on hand, mostly scrap and recycled parts with the possible exception of a motor and VFD.

One of the reasons for the short center distance is portability. I need to keep the weight of the bed down to something that can be moved by two people without equipment so it may not weigh more than 150 lbs or so (just the bed). Same for the headstock and tailstock as well as the main drive. Further details are to be worked out as the build progresses. This is a design as I go project although I already have nearly all the elements worked out in my head.

I decided to make the most difficult and most critical part first, the spindle. I used a large chunk of 300 series stainless steel I had laying around. It was cleaned up and the required bearing seats and spindle nose threads laid on. It is designed to be able to use my chucks from the SB so it has a 1 1/2" x 8tpi nose. The next step was the hard one, boring out a little over 12 inches of somewhat work hardened stainless steel.

It will have a through spindle capacity of 1 inch. That is the most the nose diameter can accomodate and still also accomodate a #4 morse taper. I am using MT4 with a sleeve to make it possible to use my existing tooling.

The spindle bearings are some that were given to me by a board member, Tryp, when he moved back east. He is also the person who gave me my Whipp 16 Shaper.

The main spindle bearing is a SKF 5310 CZZG twin row angular contact bearing with an RPM rating of about 6000 and a dynamic radial load capacity of 10 tons, axial capacity of 8 tons. ID is 5 cm and OD is 11cm. The spindle tail bearing is similar but only single row.

Here are some pictures. Fortunately for the boring operation I have a very good quality set of Sheffield Steel drill bits that are up to the job of drilling hard SS. Still, it wasn't easy with the job requiring proceeding in small stages. First a pilot hole is drilled on center and then a hole is driven a couple of inches with a 1/2" bit. Then that is enlarged to 3/4" to provide chip relief and the half inch is used again for another couple of inches. Then the 1" bit is used to provide chip relief for the 3/4" bit and the 3/4" is then used to drill the additional 2 inches following the lead of the 1/2" bit. This sequence is repeated until the 1" bit is the only remaining bit with enough reach and it is then powered through as far as it will go with the preceeding bore to maintain alignment.

The spindle is reversed and the same operations performed. In this case I left the nose portion bored only to 3/4" to allow for laying in the correct taper once the lathe is operational.

Total drilling time to get from the top image to the bottom image about six hours.
http://metalshopborealis.ca/pics5/lathepart1a.jpg

http://metalshopborealis.ca/pics5/lathepart1b.jpg


http://metalshopborealis.ca/pics5/lathepart1c.jpg


http://metalshopborealis.ca/pics5/lathepart1d.jpg

I will be posting more images in this thread as I complete the rest of the parts for the rear spindle bearing and drive.

Teenage_Machinist
01-01-2009, 02:29 PM
WOOT!
That looks like... T3h ub3r spindlezzzorrz (MY PERSONAL LIFE IS NOT ON TRIAL!)

deltaenterprizes
01-01-2009, 02:38 PM
Why do you have the bearing mounted while working on the spindle?

Peter.
01-01-2009, 02:41 PM
Hi Evan.

That looks like a great (and ambitious) project. I have some novice questions.

Why are you machining it with the spindle bearing in place? Is it a press-fit on the shaft and you don't want to risk damaging it by pressing it off?

Since you are building the entire lathe, why not make the shaft and leave the spindle end blank, then machine the nose thread & taper with the machine assembled?

Looking forward to seeing this project come to fruition - please update as often as possible.

Spin Doctor
01-01-2009, 02:59 PM
Didn't GW Ewan* IIRC post one he built a couple, three years back. Pretty good swing with screw cutting capabilities?

* Seeing as how the adnim has disabled the members list I think that is the name.

S_J_H
01-01-2009, 04:28 PM
Evan,
Very nice work on the spindle. Now that is quite a bearing!

I will be looking forward to your future posts on this project.

Steve

J Tiers
01-01-2009, 04:57 PM
Your quickest way in would be riser blocks....... but for 16" you would need about 3" or so. Might be a bit large for your bed.

If you could live with 12 to 14" your blocks would be more reasonable.

I fully understand the approach you are using, since you may be in somewhat of a machine desert, at least for usable ones. When the local shops get done with one, I suspect there isn't much left..........

quasi
01-01-2009, 05:27 PM
Wow, that is some bearing. I am really looking forward to this thread. I hope all the nay sayers, high jackers, back seat drivers, .... stay out of this thread and let it stay on topic. Building a tool with your own ideas, design, and with what you have at hand is very much in the tradition of Maudslay, Whitworth, and other original concept types.

John Stevenson
01-01-2009, 05:43 PM
Only thing I can see that matters is that double row bearing is a preset and non adjustable.

.

Evan
01-01-2009, 05:47 PM
That bearing is intended to be a very tight press fit. I made the bearing seat wider than the bearing with a few tenths of a taper to help start it on. Once in place the bearing doesn't sit on the taper. I tried it for fit and it worked great. Too great. I didn't want to press it back off and there was no reason to do so so I left it in place.


Since you are building the entire lathe, why not make the shaft and leave the spindle end blank, then machine the nose thread & taper with the machine assembled?



The machine won't have threading capability, at least not to start with.

I already have two machines that can do threads. This lathe will be outfitted for computer control at some time in the future. That will also include spindle positioning, not just spindle encoding.

garyphansen
01-01-2009, 05:47 PM
"I need to keep the weight of the bed down to something that can be moved by two people without equipment so it may not weigh more than 150 lbs or so (just the bed)."

Oh come on Evan, you of all people should be able to figure out how to move a 1000 pound lathe around you shop all by your self. A friend and I put my 2000 pound LeBlond in my basement in about an hour with out any death or injuries. Gary P. Hansen

Evan
01-01-2009, 05:56 PM
Only thing I can see that matters is that double row bearing is a preset and non adjustable.

This bearing is what is known as a Conrad style construction. The contact angles diverge from center instead of converging. According to SKF it can be preloaded in either direction and this style with diverging contact angles gives it high rigidity.

Peter.
01-01-2009, 06:00 PM
Thanks Evan yeah I should have spotted that - you did put it in the original post *embarassed*.

Bazz
01-01-2009, 06:21 PM
Evan I make lathes all the time and I wonder why you chose SS for material for the spindle I always thought that SS expands more with heat and can cause problems if your bearing gets hot or warm and I would be affraid for one of those days when the SS thread will grip to a Chuck back plate and cause big problem, Here is an example of a 32 inch lathe that I made


http://http://i42.photobucket.com/albums/e344/Bazzshop/th_IMG_0123.jpg (http://s42.photobucket.com/albums/e344/Bazzshop/?action=view&current=IMG_0123.jpg)

Good luck with your built
Bazz

J Tiers
01-01-2009, 08:46 PM
I had always thought (and New Departure helped me think it) "conrad" bearings were the traditional groove types...... Which might not be the best type.

I am glad you mentioned preload.......

OLD type New Departure double row were available in zero clearance preloaded versions. The preload was established inside the bearing as manufactured.

Logan used that style for their early machines, with no external preload system. If you ever replaced the bearings, that type is no longer made* and you would get a bearing (as I did FROM Logan) that is chattery and almost useless.**

The cure is to retrofit preload for the nasty thing, at which point it becomes very usable and perfectly OK. That isn't necessarily easy on an existing design, but if you are scratch building it's not an issue.

Logan changed to an externally preloaded system pretty fast. The new system uses large belleville spring washers inside the headstock.

When you say "diverging angle", exactly what do you mean? There are two ways the angle could 'diverge".....

The most rigid, again per N-D, is to have the lines of pressure converge outside the outer race, which makes the "pressure diamond" wide along the shaft. The balls contact the inner race near the bearing faces, and contact the outer race near its middle.


* at least not made for sale unless ordered at high cost and minimum orders.

** the clearance was almost 0.0013 for the bearing I had. Preload with belleville washers and an extra bearing fixed it.

Evan
01-01-2009, 09:55 PM
This is the bearing configuration:

http://metalshopborealis.ca/pics5/5310.jpg


I am nearly finished with the spindle and will put up some pictures of the completed part tonight some time. It is designed for easy preload adjustment. One thing I learned over the years is that if you are going to put an adjustment on a machine it better be easy to adjust. If it isn't it will be ignored until there is a real problem. If you can't make it easy to adjust you are better off to spend the extra money on tighter specs and hardpoint component location.


The reason I used SS for the spindle is because it was what I had on hand the right size. CLE is about the same as steel although the conductivity is poor. That will make no difference.

J Tiers
01-01-2009, 10:11 PM
yep that's the one...... converge on OD, wide "pressure diamond". Textbook example.

Doozer
01-02-2009, 12:00 AM
Looks awesome so far.
I am surprised you did not make a larger chuck mount, and go with a 5C spindle.
I know your SB uses 1 1/2-8 and that is why you stuck with it, but 5C is so sweet. You could make a threaded adapter for your SB to go from 1 1/2-8 to 2 1/4-8. or whatever it is that SB also uses. Then you could still switch chucks. Perhaps 5C is not your thing, I get that. But you also want 16" of swing? with a small 1 1/2" chuck mount? I just wanted to spark your ideas before you get to far into it. FWIW, an A-type spindle nose is easier to make than a camlock, and even more rigid. I never minded the bolts. Just thinking out loud. Sweet bearings, by the way.
--Doozer

Bguns
01-02-2009, 12:28 AM
What is the SB Part Number for the Adjustable Locking Unit on Belt Adjustment? :)

Evan
01-02-2009, 12:28 AM
This is the finished spindle except for four bolt holes for the drive pulley. I'm cutting it short tonight because it's clear sky for the first time in weeks and I want to take some pics with my new drive gears.


There is a gap between the chuck back and the register. I need to skim a couple of tenths off as it is just a bit tight winding on.

http://metalshopborealis.ca/pics5/lathepart1e.jpg

This is the preload adjuster. The rear bearing is a sliding fit , just barely. The threaded part is a press fit on the spindle but I will pin it also to make sure it doesn't move.

http://metalshopborealis.ca/pics5/lathepart1f.jpg

This is the drive pulley that I found at the dump. It should do nicely. It needs four threaded holes for bolts and will also get a spindle bore extension with a flange that clamps the drive pulley to the spindle.

http://metalshopborealis.ca/pics5/lathepart1g.jpg

John Stevenson
01-02-2009, 05:33 AM
This is the bearing configuration:

http://metalshopborealis.ca/pics5/5310.jpg




No split ring configuration so it's a preset. the preload adjuster you are building isn't a preload adjuster at all but just an end float adjuster.

Putting load on that adjuster will only put pressure on one set of bearings and reduce it from the other.

To use this double angular contact design correctly you need either a split race double angular contact bearing or two separate back to back bearings with the adjustment nut directly behind the bearings.

The way you have it you might as well just use one bearing.
Those double bearings is designed mainly for wheel bearings on cars that need maximum axial capacity, which as you posted in your first post is 8 tons, nearly equal to the radial load capacity of 10 tons.

Ideal for cornering loads but try any wheel bearing after a few 1,000 miles and it always has a little bit of shake, no problem on a car but image the surface finish if that were a lathe.

.

Evan
01-02-2009, 07:05 AM
I have never seen a car with a bearing like this John. The configuration of this bearing is exactly the same as a back to back arrangement of a duplex pair of 7000 series angular contact bearings. That is a standard machine tool spindle configuration.


Ideal for cornering loads but try any wheel bearing after a few 1,000 miles and it always has a little bit of shake, no problem on a car but image the surface finish if that were a lathe.



Since I have no intention of doing any heavy cornering with this bearing on or off road I don't expect it to develop any looseness or shake. If for some unimaginable reason it does the "end float adjuster" will take up any slack and apply a preset bias to the bearing in the direction required when using it as a spindle bearing. I do believe that is known as "preload". My South bend, which has plane bearings and a single separate axial load only thrust bearing has an end float adjuster. While it looks the same it doesn't quite do the same thing.

John Stevenson
01-02-2009, 07:39 AM
I have never seen a car with a bearing like this John. The configuration of this bearing is exactly the same as a back to back arrangement of a duplex pair of 7000 series angular contact bearings. That is a standard machine tool spindle configuration.

No it is NOT.
Machine tool spindle configuration uses either two separate bearing or a split double so that both bearings can be adjusted load face to load face.
Often like the Bridgeport they use ground inner and out spacers to achieve the right preload.

There is no way in this bearing design to keep a preload on those two races other then what the manufacturer has deemed acceptable given the classification of the bearing.


Do a Google on double row angular contact wheel bearings.
or see here;

http://www.ourbearings.com/wheel_bearings.htm



If for some unimaginable reason it does the "end float adjuster" will take up any slack and apply a preset bias to the bearing in the direction required when using it as a spindle bearing. I do believe that is known as "preload".


That is true but it will only apply it to one side, as it applies it to one side, the one next to the chuck it will reduce it from the other side so in effect you are running on one bearing.
It is not an unimaginable reason it's called wear.

Evan
01-02-2009, 09:39 AM
No it is NOT.
Machine tool spindle configuration uses either two separate bearing or a split double so that both bearings can be adjusted load face to load face.


Not always.



Twin Spindle - Twin Turret

Model: 20A/30N/40N Series

FANUC 0i Mate Controller
High rigidity and heavy cutting
Live turret with C axis (including Mechanic & Control system.
6 driving tools onthe live turret offering milling, tapping and drilling operations
25-4000 rpm for the live turret
Double row high precision roller bearing and angular contact thrust double row bearings equiped high precision spindle
Programmable tailstock





http://metalshopborealis.ca/pics5/acbearing.jpg

http://www.nachiengineering.com/pdf/B-MT.pdf

[quote]That is true but it will only apply it to one side, as it applies it to one side, the one next to the chuck it will reduce it from the other side so in effect you are running on one bearing.
It is not an unimaginable reason it's called wear.

I wonder how long that will take? I also wonder how much external preload it would take to reduce the internal preload to zero on a bearing rated for 10 tons.

John Stevenson
01-02-2009, 10:08 AM
Not always.




[quote]
http://metalshopborealis.ca/pics5/acbearing.jpg

Thank you for than link Even you have answered my post.

Look carefully at the INNER ring, it's a 3 part ring, 2 bearings and a central spacer that sets the preload.

The outer maybe a one piece outer but the inner like most preloadable double angular contacts in in multiple pieces. That setup would have had the adjustment directly behind the bearing, NOT on the other end.

Here's the headstock of a CVA lathe which is a copy of the 10EE

http://www.stevenson-engineers.co.uk/files/CVA%20headstock.jpg

Note the two bearings back to back with spacers 18 and 19 in-between and the locknut and lock 13-14 that pushes the thrust #16 onto the inner bearing.


I do know what I am talking about about on spindle bearings believe me, I don't suppose you came across many 50mm bore by 110mm OD 5310's in photocopier's did you ? :D

.

Evan
01-02-2009, 10:43 AM
I do know what I am talking about about on spindle bearings believe me, I don't suppose you came across many 50mm bore by 110mm OD 5310's in photocopier's did you ?



Not very often. Xerox didn't sell a lot of the very big machines. They cost near half a million dollars and require a 50 amp service for the drive motor and a 20 amp service for the rest.

From NSK


Double-row angular contact ball bearings are basically two single-row angular contact ball bearings mounted back-to-back except that they have only one inner ring and one outer ring, each having raceways. They can take axial loads in either direction.

http://www.tec.nsk.com/Handbook.asp?menu=1,0,0,0&PageID=/TypesAndFeatures/DoubleRowAngularContact.html


This is the configuration I am using, as recommended by NSK.

http://metalshopborealis.ca/pics5/acbearing2.jpg


I do know what I am talking about about on spindle bearings believe me,

I am beginning to wonder.

J Tiers
01-02-2009, 11:31 AM
It is not an unimaginable reason it's called wear.

Ball bearings DO NOT WEAR (if ball cages stay lubricated).

A ball bearing that wears is contaminated with some crap that acts as a lapping compound.

The failure mode for a ball bearing is fatigue cracking of the surface, with spalling off of pieces.

It takes a while, and is a function of both the total cycles (shaft turns) and the loading. More loading, earlier fatigue failure.

I do however, agree that the bearing in question may or may not be internally preloaded. if it IS internally preloaded, as New Departure did for their double row bearings, then your concerns are not applicable.

if it is NOT internally preloaded, then there is "clearance", only one row will be loaded, and an external preload will be required, as I mentioned referencing the Logan bearings, OEM 1942 parts vs new replacements from Logan.

The split is not the only way to preload. A one-piece bearing can be preloaded by selecting the balls in both races so as to have the proper interference to develop the preload, and by specifying the fit in the pocket or on the shaft. It's a bunch harder, I'd suspect, and would require the bearing to be loaded with fewer than the maximum number of balls, or you'd be hard--pressed to get all the balls in.

Spin Doctor
01-02-2009, 11:39 AM
Evan, I was going to stay out of this but................... John does know what he is talking about. So do I. I spent a good portion of my working life rebuilding precision machining spindles and doing adjustments/diagnosing problems on them in service. What I was going to suggest if you want to keep the costs down on this project is to use two 72XX series non-precision bearings in a DB arrangement on both ends of the lathe spindle. The rear has to be able to float axially in the bore to allow for heat expansion while the front set has to be captured in its bore by its retainer (.005" is fine). The front set can also have a set of inner and outer spacer to adjust preload (a really good idea it to make the spacers equal to the width of two bearings so the set of two can be turned into a quad set). The bearings should not be pressed into either bore but have either a slight slip fit (.0005" ) with front set being maybe size on size. The only advantage to the double row sealed bearing you showed is its seal.

Evan
01-02-2009, 11:46 AM
The only advantage to the double row sealed bearing you showed is its seal.


Not so. It's free instead of costing $200. That's a big advantage. In my original post I said I was building this with what I have on hand. This is what I have on hand and there is no reason it won't work. I am not designing a commercial product that must be produced to compete in the market. I am designing something that will allow me to turn larger diameter work pieces than my SB9. It should do that very well.

lazlo
01-02-2009, 12:04 PM
No it is NOT.
Machine tool spindle configuration uses either two separate bearing or a split double so that both bearings can be adjusted load face to load face.
Often like the Bridgeport they use ground inner and out spacers to achieve the right preload.

There is no way in this bearing design to keep a preload on those two races other then what the manufacturer has deemed acceptable given the classification of the bearing.

John's right -- you can't preload a double row angular contact bearing, because the two bearings are fused together. That's why they're not used in machine spindles. Spindle bearings are individual duplex or triplex pairs, and the preload spacer wedges the inner or outer races of the two bearings together.

Double-row angular contact bearings are usually used in non-precision applications where there are dual axial and radial forces -- compressors, pumps, screw drives, ... If you got the bearing from a photocopier, it's probably the latter.

If you're looking for a large spindle bearing on a budget, one suggestion would be to use a single precision tapered roller bearing. Then you can use your existing preload threads to preload the cup into the cone.

Evan
01-02-2009, 12:17 PM
That's why they're not used in machine spindles.

It will be here. Care to bet that it won't work?

lazlo
01-02-2009, 12:21 PM
It will be here. Care to bet that it won't work?

Sure, it'll work, but it will have more runout than you'd probably like -- about the same runout as any other non-precision bearing. Probably a lot more than your South Bend.

The reason you pre-load the two angular contact bearings on a machine spindle is to reduce axial and radial runout. You can't do that with a double-row bearing.


If you're looking for a large spindle bearing on a budget, one suggestion would be to use a single precision tapered roller bearing. Then you can use your existing preload threads to preload the cup into the cone.

Edit: Evan, if want, I have a Class 3 (ABEC-5) precision tapered roller bearing that I've been saving for my Millrite spindle. I'd be glad to donate it to your project :)

topct
01-02-2009, 12:33 PM
Evans spindle and bearings will work. Even though the swing will be in the 16 to 18 inch range I doubt if its going to see the loads normally equated with such a large swing on a lathe. The 1 1/2" spindle nose will limit that.

I'm more interested in what the bed and cross feed are going to look like.

Evan
01-02-2009, 12:42 PM
Evan, if want, I have a Class 3 (ABEC-5) precision tapered roller bearing that I've been saving for my Millrite spindle. I'd be glad to donate it to your project

Thanks for the offer. I might take you up on it. I can measure the runout right now by chucking it up and indicating to the outer race. It's internally preloaded so it should be an accurate test.

What are the dimensions on that bearing Robert? I will not be making another spindle.

BTW, I don't see how the method of attaching the chuck to the spindle makes a difference to the load capacity. The back plate is brought into hard contact with the register on the spindle. It's the flexibility of the spindle that will determine how much deflection occurs. The threaded nose is plenty strong enough to keep the chuck and back plate properly secured.

lane
01-02-2009, 12:55 PM
Not so. It's free instead of costing $200. That's a big advantage. In my original post I said I was building this with what I have on hand. This is what I have on hand and there is no reason it won't work. I am not designing a commercial product that must be produced to compete in the market. I am designing something that will allow me to turn larger diameter work pieces than my SB9. It should do that very well.

Way to go Evan.This group thanks they are going to he moon again.I would bet any bearing you would use would work for your life time.
Save this thread Evan .And when you get it finished . Check out the run out and every thing else they are fussing about and let us know what it is. I will bet you can`t hardly measure it.

J Tiers
01-02-2009, 01:28 PM
The reason you pre-load the two angular contact bearings on a machine spindle is to reduce axial and radial runout. You can't do that with a double-row bearing.



WRONG.

The reason you preload ANY bearing is to reduce deflection under load.

And you of course CAN do that with a double-row bearing.

If it is INTERNALLY preloaded, you don't HAVE to preload it again, that would be superfluous. As with the original Logan bearings.

If it is NOT, as with the replacement Logan bearings, then you HAVE to preload to eliminate clearance, at least, and deflection of course.

But the effect specifically on runout is not the reason. That would be far more controlled by class of bearing. Unless of course, you count clearance slop as equal to runout, which it is not.

Load....

I think the point was more the SIZE of the spindle limiting loading..... a 1.5" spindle would be associated with a 9" or 10" lathe, while a 12" would have 2 1/8", and larger proportionately bigger spindles.

precision..........

I suspect that bearing will work as well as its class allows it to. Since we dn't KNOW that class, we have no reason to suspect it is necessarily bad. or good, for that matter.

John Stevenson
01-02-2009, 01:38 PM
OK it will work, all I was pointing out for anyone who fancied copying what Even is doing is that there are better ways and just as cheap as single angular contact bearings are used on many things, Mini front wheel hubs for one and I'll bet they are only $5.00 a bearing from the discount car part places.

Lets face it most Chinese import machines often have just a deep groove ball race back and front and they work.

Evan is trying to read more into his choice of bearing than is actually there, OK so it's a double row angular contact bearing, made out of billet but it's not the BEST double angular contact bearing out there and the reason has been explained. Evan managed to gloss over his incorrect link quite conveniently.

Spin Doctor summed it up and if he hasn't the credentials then no one has.

Anyone want to take bets on what the published run out will be ?

.

BillH
01-02-2009, 01:46 PM
OK it will work, all I was pointing out for anyone who fancied copying what Even is doing is that there are better ways and just as cheap as single angular contact bearings are used on many things, Mini front wheel hubs for one and I'll bet they are only $5.00 a bearing from the discount car part places.

Lets face it most Chinese import machines often have just a deep groove ball race back and front and they work.

Evan is trying to read more into his choice of bearing than is actually there, OK so it's a double row angular contact bearing, made out of billet but it's not the BEST double angular contact bearing out there and the reason has been explained. Evan managed to gloss over his incorrect link quite conveniently.

Spin Doctor summed it up and if he hasn't the credentials then no one has.

Anyone want to take bets on what the published run out will be ?

.

.0013 is my wild guess

Evan
01-02-2009, 02:10 PM
Check out the run out and every thing else they are fussing about and let us know what it is. I will bet you can`t hardly measure it.

Normally you would be right Lane but I have a Tesa dial indicator that is graduated at one micron per division. That's 0.0000397 inches per division.

http://metalshopborealis.ca/pics5/tesa.jpg
http://metalshopborealis.ca/pics5/tesa4.jpg
I centered up the bearing journal to the best of my ability in the 4 jaw. I was able to get it to about plus/minus 3 microns deviation per rotation. That's +/- 0.00012", a touch over one tenth runout each side at the journal. It took me half an hour before I was convinced I couldn't make it closer than that. I will have to investigate why.

http://metalshopborealis.ca/pics5/tesa2.jpg

Then, measuring to the outer race and holding the outer race still while rotating the spindle I measured about +/- 4 microns per rev.
I rotated the bearing to various positions and always obtained the same result. I also saw the same result with the lathe running slowly in back gear.

http://metalshopborealis.ca/pics5/tesa3.jpg

So, it appears that the bearing has a couple of microns runout. Thanks for your offer Robert but I don't think I will need that bearing.

2 microns = 0.00008 inches.

BillH
01-02-2009, 02:28 PM
Normally you would be right Lane but I have a Tesa dial indicator that is graduated at one micron per division. That's 0.0000397 inches per division.


So, it appears that the bearing has a couple of microns runout. Thanks for your offer Robert but I don't think I will need that bearing.

2 microns = 0.00008 inches.
Hmm, I was one decimal place off

aboard_epsilon
01-02-2009, 02:41 PM
Thought the run out of bearings was measured whilst levering on them ?

dont see you doing that in the pics .

well you cant do that whilst its in the southbend chuck......youd get the run-out of the southbend too.

so are your measurments valid ?

all the best.......markj

Spin Doctor
01-02-2009, 02:43 PM
I have to admit I am interested in seeing the cross-slide and saddle arrangement too. Its just the spindle set-up is going to be limited to fairly light cuts IMO*. With out seeing just what Evan has in mind there I wonder if he is going to go with a bar bed?

* What will be more interesting is seeing just what projects the machine is supposed to allow to be done. Something astronomical perhaps?

Evan
01-02-2009, 02:49 PM
Thought the run out of bearings was measured whilst levering on them ?



This is an internally preloaded bearing so no external load is required to measure runout. The +- 3 microns I am measuring is probably the runout of the SB spindle. That doesn't matter because I am measuring the difference in runout between the journal and the outer bearing shell.


What will be more interesting is seeing just what projects the machine is supposed to allow to be done. Something astronomical perhaps?


To begin with I sometimes get used 10" aluminum grinding wheel discs. I need to trepan the outer rim off and can't do that in my lathe.

John Stevenson
01-02-2009, 04:32 PM
Then, measuring to the outer race and holding the outer race still while rotating the spindle I measured about +/- 4 microns per rev.
I rotated the bearing to various positions and always obtained the same result. I also saw the same result with the lathe running slowly in back gear.


So, it appears that the bearing has a couple of microns runout. Thanks for your offer Robert but I don't think I will need that bearing.

2 microns = 0.00008 inches.

So the South bend also only has a run out of 0.00008"
Why does that not surprise me ?? :rolleyes:

John Stevenson
01-02-2009, 04:40 PM
The +- 3 microns I am measuring is probably the runout of the SB spindle.

Why the fück did we ever bother making cylindrical grinders and 10EE's for? Why not keep churning these old flat belt SB's out.

Lets face it you can get a mint SB for $1500 and a recon 10EE is only $48,000

Do you want a bridge to go over William's Lake ? :)

.

lazlo
01-02-2009, 04:42 PM
The reason you pre-load the two angular contact bearings on a machine spindle is to reduce axial and radial runout. You can't do that with a double-row bearing.

WRONG.

The reason you preload ANY bearing is to reduce deflection under load.

Jerry, you said this last time during the Bridgeport spindle bearing discussion, but you still don't get it.

Preload, by definition, removes the internal clearance of a bearing by wedging the inner and outer races.

Preloads
http://www.rotoprecision.ca/Products/Miniature_Bearings/Internal_Geometry.html

Preloading is used to remove the internal clearance of a bearing and is achieved by applying a permanent thrust load in an axial direction. Preloading is used to eliminate radial and axial play, increase system rigidity, reduce run out, increase the assembly’s tolerance for vibration, and reduce operating noise.

So Bridgeport, for example, used to take a pair of common 6207 radial ball bearings, grind the inner races, and preload-out the bearing runout. Bingo: Poor Man's angular contact bearing. Bridgeport did that on their Boss leadscrew bearings too.

Similarly, the Monarch 10EE used ABEC-5 bearings that were custom preloaded to God-like precision. Not as good as Evan's South Bend though ;)

John Stevenson
01-02-2009, 04:56 PM
Ball bearings DO NOT WEAR (if ball cages stay lubricated).

A ball bearing that wears is contaminated with some crap that acts as a lapping compound.


I'll have to tell that to the motor rewinders next time they order another 5,000 bearings as a job lot.

"Hey George my mate on the internet says that bearing do not wear, A ball bearing that wears is contaminated with some crap that acts as a lapping compound."

I can just hear the answer,
"Well then, ask your mate where the crap comes from then when we fit factory sealed and greased bearings and running in a clean environment they are worn after a couple of years "

Then ask him if he heard of Brinnell or is that a brand of dog food over there ?

.

rotate
01-02-2009, 05:38 PM
I'll have to tell that to the motor rewinders next time they order another 5,000 bearings as a job lot.

"Hey George my mate on the internet says that bearing do not wear, A ball bearing that wears is contaminated with some crap that acts as a lapping compound."

.

If the ball bearings are perfectly spherical and the races are perfectly smooth, then there's only the rolling action which means that it should in theory never wear. However, no surfaces are perfectly flat or round and is limited by the manufacturing process and ultimately the size of the steel grain itself. Think of it as n-th sided polygon rolling in n-th sided polygon.

Evan
01-02-2009, 05:49 PM
John,

Would you like to see a video of the measurement process? It appears you don't wish to take my word for it. Careful what you ask for though.

S_J_H
01-02-2009, 05:51 PM
Not exactly that many of us who take on a custom lathe build!

A lot of guys have built the smaller machines, myself included. But a 16" swing lathe for metal? That's a pretty big undertaking!
This nice thing is we have so much info available. And much of what were very complex mechanical gearing and devices needed on a good lathe for the feeds and threads, can now be done easily and simply with cnc. This greatly simplifies building a usable lathe in the shop.
Hey, if the bearing setup works, then great. If not, then Evan can switch to plan B and all he is out is some time and maybe some material.
I would give it a try.
Looking forward to see the headstock and lathe bed!

Steve

Evan
01-02-2009, 05:54 PM
Not as good as Evan's South Bend though

It uses plane bearings and the spindle is hardened and precision ground. Why should it have significant runout? As long as it is round the measured runout should be very close to zero. That is what is being measured in the baseline case, the roundness of the spindle.

Rolling element bearings will never be as good as hydrodynamic plane bearings.

lazlo
01-02-2009, 06:08 PM
According to the South Bend catalog, a SB "toolroom" lathe had a runout spec of .0003", and a SB "engine lathe" (everything else not classified as a toolroom lathe) has a runout spec of .0005".

This is measured on a 12" test bar.

Evan
01-02-2009, 06:23 PM
That's nice. I don't really know where the +- 3 micron runout comes from. I am assuming it is the spindle as I tried for quite a while to reduce it and couldn't. It's what I measured and I measured it accurately. If you don't like it or believe it then suit yourself. Unless you can demonstrate an error in my method though you cannot show that my measurements are incorrect.

S_J_H
01-02-2009, 06:33 PM
Not sure what South Bend meant by those specs. My SB9 which has my own bronze bearings has much less than .0003" run out.
The run out is going to be determined by 2 important things with a plane bearing.
One, how round is the spindle.
Two, how consistent is the oil film between spindle and bearing.

Without oil there is up to .001+" free clearance between spindle and bearing surface.
Once the oil film is established then run out should be about as good as the spindle was ground unless something is very wrong.
.0005" is ridiculous.
Even a mini lathe spindle with cheap deep grooves is only around .0003".

John Stevenson
01-02-2009, 06:45 PM
What is being measured ? if you are measuring round on or close to the bearing then it should be as close to 0.000000000 [ approx ] as possible.

If you are measuring a test bar fitted into the spindle taper both at the chuck end and 12" out then two variables come into play.
[1] the relationship between the taper eccentricity compared to the bearing diameter and
[2] the alignment along the spindle centre line of the taper.

[1] will give you run-out and [2] Will give you extended run-out.

Most test spec sheets, like Schlesinger's work on the test bar fitted to the taper.

.

S_J_H
01-02-2009, 07:12 PM
John, I see. That measurement takes into account several variables.

I can see this measurement being important for collet use for example.

It's not a runout measurement that is very valid for this discussion right now IMO.

Steve

noah katz
01-02-2009, 07:38 PM
"If the ball bearings are perfectly spherical and the races are perfectly smooth, then there's only the rolling action which means that it should in theory never wear."

Because of the varying surface speed of the balls at different distances from the center, there will be scrubbing between the balls and the races.

I can't think of anything except a needle bearing that is purely rolling.

lazlo
01-02-2009, 07:39 PM
Not sure what South Bend meant by those specs. My SB9 which has my own bronze bearings has much less than .0003" run out.

Even a mini lathe spindle with cheap deep grooves is only around .0003"

Steve, a mini-lathe isn't anywhere close to 3 tenths runout! How are you measuring these values?

My mini-lathe has about a thou of runout, which is pretty typical. Here's a copy of Gagetbuilder's Sieg 7x10 test report, which shows a measured runout of 8 tenths, and an allowable runout spec of 1.6 thou. That's not surprising, since a common (non-precision) radial ball bearing has a max runout of 3 thou (http://www.abtbearing.com/dg_abec.html):

http://www.gadgetbuilder.com/Report.jpg

lazlo
01-02-2009, 07:47 PM
And for some perspective, the Deckel toolroom mills have a runout spec of 4 tenths:

http://i164.photobucket.com/albums/u15/rtgeorge_album/deckelTIR.gif[/QUOTE]

darryl
01-02-2009, 07:48 PM
What a crummy bearing for that application. Best would be to get rid of it now- my address is---:)

Looking at the drawing, it would seem that the inner race is pretty thin at its center. You could have ground through that to separate the inner race into two pieces, then you'd be able to set the preload yourself. ( I take a bow, and offer to show my credentials as a HSBE- home shop bearing engineer) :)

S_J_H
01-02-2009, 07:57 PM
Robert, yes yes , I agree now that I know you are talking about run out using a test bar!!
But that's also a measurement of how well the internal taper is ground and has nothing at all to do with the bearings.
Measure the outside of a mini lathe spindle and you'll get around .0003" runout.


If using a center one would usually return the tip true and now that horrendous internal taper runout is gone and all that is left is what's in the bearings.

Steve

Evan
01-02-2009, 07:57 PM
"If the ball bearings are perfectly spherical and the races are perfectly smooth, then there's only the rolling action which means that it should in theory never wear."

Because of the varying surface speed of the balls at different distances from the center, there will be scrubbing between the balls and the races.

I can't think of anything except a needle bearing that is purely rolling.




The shape of the grooves in ball bearing races is intentionally not exactly the same as the ball. Under very light load the ball will have a point contact on each race with a pure rolling action. As the load is increased both the ball and the races deform at the point of contact with the result that the point of contact becomes a contact patch.

The difference in actual position at the edges of this patch and the theoretical position is extremely small even with a significant load. How much deformation takes place is also dependent on if and how fast the bearing is turning. At a standstill the deformation is at maximum which is why the maximum load spec for a static load on a non rotating ball bearing is much lower than the running spec.

As the load is increased while the bearing is turning the deformation of the components generates heat. The balls heat up more than the races as they have much less mass and can only dissipate heat via contact with the race. As they heat up the properties of the metal change. Above about 150 to 200 degrees F those properties change enough to weaken the balls. How fast this happens depends on the load and rpm. Part of the load is caused by the centrifugal acceleration of the bearings against the outer race.

If the balls become hot enough they lose strength and this will happen before the races. When that occurs the material in the contact patch will begin to be deformed enough to exceed the plastic yield limit. When that happens the surface layer of tbe ball will begin to form microcracks all over the surface of the ball. The next stage is that pieces of the surface will begin to break away, a process called spalling. When this occurs those pieces then become foreign objects in the races and the further destruction of the bearing under load is both assured and almost immediate.

Robert, the spec on the Deckel is listed as "(maximum) permissible". I would not expect to see it at or even near that spec limit.

lane
01-02-2009, 08:07 PM
OK it will work, all I was pointing out for anyone who fancied copying what Even is doing is that there are better ways and just as cheap as single angular contact bearings are used on many things, Mini front wheel hubs for one and I'll bet they are only $5.00 a bearing from the discount car part places.

Lets face it most Chinese import machines often have just a deep groove ball race back and front and they work.

Evan is trying to read more into his choice of bearing than is actually there, OK so it's a double row angular contact bearing, made out of billet but it's not the BEST double angular contact bearing out there and the reason has been explained. Evan managed to gloss over his incorrect link quite conveniently.

Spin Doctor summed it up and if he hasn't the credentials then no one has.

Anyone want to take bets on what the published run out will be ?

.


John is probably right . But it is what Evan has and he said he was going to use what he had and this is it . I have done the same thing and it worked . Built a surface grinder once with a pair of hand fitted Barten bearings and it worked just fine.

Would some one tell me why this group get so carried away over bearings . We have all been here more than once.

lazlo
01-02-2009, 08:11 PM
Measure the outside of a mini lathe spindle and you'll get around .0003" runout.

If you squint really hard, you can read that the first test on the Sieg chart is testing the runout of the spindle nose. That has a max runout of .04 mm, or 16 thou.

Or put it a different way: there's no way that a Mini-lathe is going to come anywhere close to a Deckel's runout :)

lane
01-02-2009, 08:12 PM
Normally you would be right Lane but I have a Tesa dial indicator that is graduated at one micron per division. That's 0.0000397 inches per division.

http://metalshopborealis.ca/pics5/tesa.jpg
http://metalshopborealis.ca/pics5/tesa4.jpg
I centered up the bearing journal to the best of my ability in the 4 jaw. I was able to get it to about plus/minus 3 microns deviation per rotation. That's +/- 0.00012", a touch over one tenth runout each side at the journal. It took me half an hour before I was convinced I couldn't make it closer than that. I will have to investigate why.

http://metalshopborealis.ca/pics5/tesa2.jpg

Then, measuring to the outer race and holding the outer race still while rotating the spindle I measured about +/- 4 microns per rev.
I rotated the bearing to various positions and always obtained the same result. I also saw the same result with the lathe running slowly in back gear.

http://metalshopborealis.ca/pics5/tesa3.jpg

So, it appears that the bearing has a couple of microns runout. Thanks for your offer Robert but I don't think I will need that bearing.

2 microns = 0.00008 inches.


Some of that is your south bend I think also. After you get the real housing built for the spindle you are making and the spindle all buttoned up check again it Will be closer I bet.

Evan
01-02-2009, 08:12 PM
Would some one tell me why this group get so carried away over bearings . We have all been here more than once.

Good question. I had the same sort of static over my choice to use PTFE linear bearings on my mill. Plenty of comments were offered that they wouldn't work even though I explained what I was doing to deal with the possible issues. It's deja-vu all over again. (Yogi Berra)

I will have to reconsider what I am going to post on this project. I don't feel like defending my choices, it's too time consuming.

lazlo
01-02-2009, 08:17 PM
Would some one tell me why this group get so carried away over bearings.

John's just poking fun at the Evan's claim of measuring 3 micron runout on a South Bend 9 :)

But once you get past the accuracy claims, it's a cool start on a lathe build.

John Stevenson
01-02-2009, 08:27 PM
I will have to reconsider what I am going to post on this project. I don't feel like defending my choices, it's too time consuming.

You said it wasn't a choice, that it came out the scrap box. I just pointed out that before anybody went out to buy what is an expensive bearing that there were better bearings available cheaper that could also be used with a better design.

I didn't say your design was wrong, I just pointed out an alternative.

I have a big stack of surplus bearing here, probably about a 3 drawer filing cabinet full that have been donated over the years and there is not one double row angular contact bearing of that size or close to it, loads of Ford half shaft bearings off Cortina's at about 35mm bore which are also double row angular contact, that's the sort of use they are for.
So if I wanted to copy Evan I'd have to go out and buy one but as I have said many cars use two single angular contact bearings and these can be obtained for not a lot of money and make a better design.

.

John Stevenson
01-02-2009, 08:32 PM
I will have to reconsider what I am going to post on this project. I don't feel like defending my choices, it's too time consuming.

No keep going I'm trying to catch you up, you have 22,325 posts and I only have 6,804 :rolleyes:

lazlo
01-02-2009, 08:33 PM
I have a big stack of surplus bearing here, probably about a 3 drawer filing cabinet full that have been donated over the years and there is not one double row angular contact bearing of that size or close to it.

The standard runout for a 1" 5200 series double-row angular contact bearing is 5 tenths. Good for a home shop lathe, but a bit more than 2 micron :)

http://iksbearing.stage.thomasnet.com/asset/Enggdata.pdf

oldtiffie
01-02-2009, 08:36 PM
Evan,

that is a top job.

Congratulations on taking it on, thinking it out, making best use of what you have as well as fending off the "barbarians", "nay-sayers" and "Doubting Thomas-es".

As usual when "bearings" comes up, there is more "charting" and "consulting" and quoting of "learned works" than there would be at an astrologist's gab-fest.

All the "ifs" reminds me of the old saw that "IF your auntie had balls she'd be your uncle", and there's more "buts" than there are in ten Billy-goats.

At least you are having a go and getting your hands dirty instead of sitting on your freckle prognosticating and pontificating. Some won't need a bridge to get over Williams Lake - they can walk over it!!

Or to (sort of) quote the Bard and the Prophet - f*ck 'em!!

I think that Lane - as usual - has injected a lot of common sense as well as confidence in your ability and the ultimate outcome.

I agree with Lane.

I rather think that your project and credibility will come out in better shape that the credibility and egos of some others.

If YOUR new lathe does what YOU want it to do, then by any measure it is a total success - irrespective of the opinion of anyone else.

Your track record is first class thus far and I can't see you blotting your copy-book on this project or anytime soon.

I am looking forward to seeing it in use.

Spin Doctor
01-02-2009, 08:38 PM
Would some one tell me why this group get so carried away over bearings . We have all been here more than once.

Because we like to tell everybody else how to do things of course:rolleyes::rolleyes:

softtail
01-02-2009, 08:39 PM
Good question. I had the same sort of static over my choice to use PTFE linear bearings on my mill. Plenty of comments were offered that they wouldn't work even though I explained what I was doing to deal with the possible issues. It's deja-vu all over again. (Yogi Berra)

I will have to reconsider what I am going to post on this project. I don't feel like defending my choices, it's too time consuming.


Keep posting please! Reconsider replying maybe, but keep posting.

oldtiffie
01-02-2009, 08:50 PM
Would some one tell me why this group get so carried away over bearings . We have all been here more than once.


Good question. I had the same sort of static over my choice to use PTFE linear bearings on my mill. Plenty of comments were offered that they wouldn't work even though I explained what I was doing to deal with the possible issues. It's deja-vu all over again. (Yogi Berra)

I will have to reconsider what I am going to post on this project. I don't feel like defending my choices, it's too time consuming.


Evan,

you - nor anyone else here - is obliged to answer any question as regard method etc.

Some may assume or believe that:
a. they are owed and can demand an explanation; and

b. that you (or anyone else) is obliged to give it.

They are 100% wrong on both counts as what others may believe in that regard may not necessarily be the case or true.

Whether you choose to or not is solely at your discretion, but having said that, I am sure that you don't need me - or anyone else -to tell you that.

lane
01-02-2009, 08:55 PM
Good question. I had the same sort of static over my choice to use PTFE linear bearings on my mill. Plenty of comments were offered that they wouldn't work even though I explained what I was doing to deal with the possible issues. It's deja-vu all over again. (Yogi Berra)

I will have to reconsider what I am going to post on this project. I don't feel like defending my choices, it's too time consuming.

No keep showing us . I like reading about what you do. beats the heck out of how do you do this are I just bought a harbor freight lathe. Besides do like i do take all of this with a grain of salt. All so no one in his right mine is going to copy what some one built because they want have the same junk to work with and they will have to improvise just like you are doing . right bearing are not.

John Stevenson
01-02-2009, 08:56 PM
Whether you choose to or not is solely at your discretion, but having said that, I am sure that you don't need me - or anyone else -to tell you that.

No we have Tiffiepedia for that.:rolleyes:

.

John Stevenson
01-02-2009, 09:00 PM
All so no one in his right mine is going to copy what some one built because they want have the same junk to work with and they will have to improvise just like you are doing . right bearing are not.

Full marks and anything off the top shelf for Lane.
That's it, Improvise with what is available and improve, don't follow the herd.
There are many ways to do something, not always a right and wrong way, just different ways.

.

Evan
01-02-2009, 10:09 PM
just poking fun at the Evan's claim of measuring 3 micron runout on a South Bend 9

I guess I will have to make the video. Not sure when, right now I am taking video footage of the moon.

Regardless of what the spec is for this bearing I was hard pressed to see any difference when measuring to the journal or to the bearing shell. That is how it is.


You said it wasn't a choice, that it came out the scrap box.

It was a choice to build with it or not. If I didn't like the bearing the project would wait.

noah katz
01-02-2009, 10:24 PM
"If the balls become hot enough they lose strength and this will happen before the races. When that occurs the material in the contact patch will begin to be deformed enough to exceed the plastic yield limit. When that happens the surface layer of tbe ball will begin to form microcracks all over the surface of the ball. The next stage is that pieces of the surface will begin to break away, a process called spalling."

Not sure if you are, but it sounds like you might be saying that bearing fatigue is due to elevated temperatures.

Bearing fatigue failure is from so-called Hertzian contact stresses, where max stress actually occurs below the surface.

I imagine what happens is that the initial fracture grows to the surface and then the little fragment pops off.

Evan
01-02-2009, 10:32 PM
Bearing fatigue is temperature dependent. The higher the temperature the faster it occurs and at lower values of load/rpm. Conversely, the higher the load or rpm, the higher the temperature for a given rpm or load.

It doesn't take a lot of temperature to start changing the properties of hardened steel. Several hundred degrees will make a big difference.

Of course gross overloading will exceed the material strength regardless of temperature. With steels as long at the maximum stress applied is less than 50% of the plastic yield limit no fatigue will occur at standard temperature.

lazlo
01-02-2009, 10:41 PM
Bearing fatigue is temperature dependent. The higher the temperature the faster it occurs and at lower values of load/rpm. Conversely, the higher the load or rpm, the higher the temperature for a given rpm or load.

Right, and the amount of preload stresses the bearing as well. With a heavily preloaded bearing, the balls are actually deforming the race as they spin.

There's a good video I found somewhere showing this -- I think it might be on the Barden "Bearing in Mind" DVD. The rest of the video is pretty lousy (mostly a Barden advertisement), but that part was pretty neat -- I'll see if I can find it.

barts
01-02-2009, 11:36 PM
With steels as long at the maximum stress applied is less than 50% of the plastic yield limit no fatigue will occur at standard temperature.

This is generally true for steels w/ a TS of less that 160 ksi, and only if the surface is polished smooth. If there are stress raisers, or if we're talking about bearing steels in a hardened condition, that 50% figure is closer to 30%..

Also, the amount of deformation at the ball-race contact point is surprising large, and the Hertzian contact stresses much larger than one would naively expect. This results in ball bearings always being loaded above the endurance limit, and means that they always will wear out due to fatigue-induced spalling.

- Bart

J Tiers
01-03-2009, 12:04 AM
I'll have to tell that to the motor rewinders next time they order another 5,000 bearings as a job lot.

"Hey George my mate on the internet says that bearing do not wear, A ball bearing that wears is contaminated with some crap that acts as a lapping compound."

I can just hear the answer,
"Well then, ask your mate where the crap comes from then when we fit factory sealed and greased bearings and running in a clean environment they are worn after a couple of years "

Then ask him if he heard of Brinnell or is that a brand of dog food over there ?

.

Don't be yelling at me, go yell at the bearing manufacturers, who obviously need to talk to you before they go printing more information......:rolleyes:

Electric motor bearings are of reasonable, but not high quality..... And as you indirectly pointed out (Brinnell), it is certainly possible and probable, that they get slightly or severely overloaded.

Before you get your mind further wrapped up in knots, take a peek at the comments about perfect roundness, etc... as above. Some of the rest I don't agree with, but for sure nothing is perfect. Electric motor bearings are *a little less perfect* than spindle bearings. ;)

Eventually, for sure, there will be spalling of the races. After that, there will be WEAR, because the freaking bearing has SUPPLIED ITS OWN abrasives. Just quit yelling and get used to it.

OK, so loading definitely affects bearing life. i surely hope THAT won't be disputed, cuz you are doomed to fail if you try.

Now WHY would it be that loading affects life? Why.... it affects the time until fatigue of the surface occurs..... due to spot overloading by those micro-defects mentioned. They don't hit the same place every time, but they do over time get a lot of hits on each spot.... roughly proportional to the total number of revolutions, since teh hits occur on any spot at a fairly consistent rate due to the random process.

Now, your overloaded belt drive motor.... operating at about 3000 rpm..... in a year of 8 hour days, it completes 288 million or so revolutions...... in two years, over 550 million revs. if they run more than 8 hours, start multiplying that number.

I suggest that is perfectly adequate to explain "wear" of bearings in electric motors...... Sheesh

S_J_H
01-03-2009, 12:21 AM
If you squint really hard, you can read that the first test on the Sieg chart is testing the runout of the spindle nose. That has a max runout of .04 mm, or 16 thou.



Geez Robert ...I'm not trying to be argumentative here.
go take a drive to your nearest H F store and bring a DI setup with you and measure a Mini lathe. Report back.
I have 3 of these damned head stocks sitting in my garage and plenty of DI's.
Think I am imagining this stuff?


And,
Testbar measurments that are internally located in the spindle have no place at all in this discussion as a method to prove a spindle bearing runout.

Steve

J Tiers
01-03-2009, 12:30 AM
Jerry, you said this last time during the Bridgeport spindle bearing discussion, but you still don't get it.

Preload, by definition, removes the internal clearance of a bearing by wedging the inner and outer races.

Preloading is used to remove the internal clearance of a bearing and is achieved by applying a permanent thrust load in an axial direction. Preloading is used to eliminate radial and axial play, increase system rigidity, reduce run out, increase the assembly’s tolerance for vibration, and reduce operating noise.


Yo...... calling Major Robert........... can you hear us Major Robert?

I still don't get it?

Excuse me, but YOU still do not get it.....

As far as clearance, it is ASSUMED that clearance is zero in any set-up system.... one would naturally snug up until that is taken care of...... unless your spindles are *a little different* from others.

And it is naturally intuitively obvious to the most casual observer that preload clearly eliminates clearance..... That isn't even a question nor an issue.... it is glaringly obvious.

Here is the part YOU do not get. let me know if I use big words that you need explanations of......... ;)

AFTER the clearance is taken up..... "preload" applies a good deal MORE force to the bearing. It may be quite a lot of added force.

What does this do?

Well it takes up a lot of flexibility of the parts INCLUDING INCREASING THE SIZE OF THE BALL CONTACT PATCHES.

if you look at a graph of deflection vs force, you will see something somewhat like a horizontal half parabola, taking deflection vertically and load horizontally.....

Any clearance is not on this chart. It would obviously be a straight vertical line.

OK, so at "low" loads, the deflection increases rapidly, but as the load increases it becomes almost a straight line, with some slope a good deal less than the initial slope.

Preload takes the applied load up past the rapidly increasing portion, and into the area of constant slope. The amount can be varied, and may at choice not get to the straight line area. That is a matter of trading deflection vs lowered life.

So why do this?

Precisely because the slope of deflection vs applied force is LOWER than it is down near the origin, with NO preload. It may be 4 or 5 times less, and every bit of reduction that can be had is good in machine tools. The manufacturer is happy to pay for increased precision with the resulting somewhat reduced life.

So, while the effects you mention are true, they utterly fail to describe the true advantage to be had.... The quoted blurb adds the key bit, as well as indeed mentioning the others.

The 'runout" mention is a little odd, , it seems they may have a different definition, or perhaps they are considering the reduction in effect of one odd-sized ball or spot due to the loading.

But the main effect of preload is a drastic increase in the stiffness of the assembly... the slope of deflection vs load.


.
.
.
BTW, preload does NOT add directly with loading....... axial loading increases force on one race, but by deflecting the spindle axially, it decreases force from the race which is applying the preload...... thus removing some preload as actual load is increased.

Evan
01-03-2009, 01:47 AM
I was just in the shop and needed to switch chucks. I took advantage of the oppourtunity to make some measurements of the spindle on my SB9 using the ultra accurate Tesa indicator. Incidentally, I picked that up at the same time as my horizontal mill. Paid $100 for a box full of metrology instruments including three similar dial indicators by Tesa and Interapid.

I am going to make a movie of the spindle runout on the SB, but not to prove a point. With such a sensitive indicator it is possible to see the spindle climb on to the oil film as it is switched on. It takes about 2 seconds during which there are several slow excursions of about 5 to 10 microns either way, not coordinated with revs. Then over the third second it quickly assumes a steady once per rev periodic deviation of about plus and minus 1.5 microns for a total excursion of about 3 microns. This was measured directly on the spindle nose at the register surface. The belt was set up fairly tight and there was no chuck or other load applied. The spindle was set to run at about 180 rpm.

It's very cool to watch and it does it exactly the same each time it is started.

oldtiffie
01-03-2009, 05:24 AM
Geez Robert ...I'm not trying to be argumentative here.
go take a drive to your nearest H F store and bring a DI setup with you and measure a Mini lathe. Report back.
I have 3 of these damned head stocks sitting in my garage and plenty of DI's.
Think I am imagining this stuff?


And,
Testbar measurments that are internally located in the spindle have no place at all in this discussion as a method to prove a spindle bearing runout.

Steve

You've got it Steve.

At this stage the bearing inner and outer concentricity is the issue, but as I guess the spindle OD and internal taper as well as the final cuts on the thread and locating collar will be done on assembly, it will be true to the machine.

And that is what counts.

I suggest we leave it up to Evan as its his project after all.

Perhaps the best way for some to prove or disprove their hypothesis is to get off the side-lines and into their own shop/s, make one themselves and let us know how they get on.

Rustybolt
01-03-2009, 11:29 AM
Evan. You might want to rethink the spindle nose. Just my 2 cents, but it looks like the perfect opportunity make a D type spindle, or any spidle type thaqt ian't threaded. I only mention it because of the tendancy for a threaded chuck to unwind when in reverse. The tendancy increases with the size of the chuck.
I know you said ths wasn't going to be used for threading, but...............sooner or later you know you're going to do it.

lazlo
01-03-2009, 11:44 AM
Geez Robert ...I'm not trying to be argumentative here.
go take a drive to your nearest H F store and bring a DI setup with you and measure a Mini lathe. Report back.
I have 3 of these damned head stocks sitting in my garage and plenty of DI's.
Think I am imagining this stuff?

I don't think you're imagining it Steve. It's not simple or easy to measure the runout of a machine tool.

I don't need to go to Harbor Freight to measure the runout on a 7x10 - I own a 7x10 mini-lathe - it's sitting on my workbench right now. As I posted yesterday, I re-measured it, and it has about a thou runout. Gagetbuilder's 7x10 has a little bit better: 8 tenths runout. If you go to the Yahoo 7x10 group, that's pretty typical, (about a thou runout), and according to the Sieg test report, the 7x10 has a runout spec of .04 mm: 1.6 thou.

So your three 7x10's have 5 times less runout than Sieg's accuracy spec, my 7x10, and Gagetbuilders', and most of the machines posted on the Yahoo 7x10 group :)

lazlo
01-03-2009, 11:52 AM
Perhaps the best way for some to prove or disprove their hypothesis is to get off the side-lines and into their own shop/s, make one themselves and let us know how they get on.


So, it appears that the bearing has a couple of microns runout. Thanks for your offer Robert but I don't think I will need that bearing.

2 microns = 0.00008 inches.

OK, I pulled the Millrite Timken roller bearing I was offering to send to Evan, and measured the runout as .006 micron -- that's 2.36220472 × 10-7 inches! I'll post some pictures later today -- I need to make a lathe with that bearing! :D

aboard_epsilon
01-03-2009, 12:06 PM
i would just use those bearings as ordinary bearings ...and plonk a heavy duty needle thrust bearing at each end of the lathe and take up the slack.

your problems gone then ..there is no arguing specs of bearings etc ..

all the best.markj

lazlo
01-03-2009, 12:09 PM
The reason you pre-load the two angular contact bearings on a machine spindle is to reduce axial and radial runout. You can't do that with a double-row bearing.WRONG.

The reason you preload ANY bearing is to reduce deflection under load.

Jerry, you said this last time during the Bridgeport spindle bearing discussion, but you still don't get it.

Preload, by definition, removes the internal clearance of a bearing by wedging the inner and outer races.

Preloads
http://www.rotoprecision.ca/Products/Miniature_Bearings/Internal_Geometry.html

Preloading is used to remove the internal clearance of a bearing and is achieved by applying a permanent thrust load in an axial direction. Preloading is used to eliminate radial and axial play, increase system rigidity, reduce run out, increase the assembly’s tolerance for vibration, and reduce operating noise.


Yo...... calling Major Robert........... can you hear us Major Robert?

Excuse me, but YOU still do not get it.....

As far as clearance, it is ASSUMED that clearance is zero in any set-up system.... one would naturally snug up until that is taken care of...... unless your spindles are *a little different* from others.


Sigh. You really need to sit down an read a bearing handbook Jerry.

All bearings have internal clearance. That's the C1, C2, C3, CN number that's printed on the bearing.

The whole point of preloading a spindle bearing is to remove the internal clearance by pushing the outer or inner races of a pair of bearings together, to remove the axial and radial clearances ("play").

The more offset you grind into a bearing, the more preload. So a light preload bearing, like you use in a Bridgeport or Hardinge spindle, has about a thou of offset ground into the inner races of the duplex pair, and you apply axial force (preload) until the races are flat again.

You're getting confused about preload versus rigidity. Bearing rigidity does increase as the bearing preload increases, because you're wedging the inner and outer races harder. But the downside to high preload is increased friction, and decreased bearing life. So in most machine tools, the spindle bearings have light preload.

http://www.eminebea.com/content/html/en/engineering/bearings/preload.shtml

Another bearing handbook that says the same thing that I posted earlier. Every bearing handbook has the same explanation:

Purpose for Preload

When a ball bearing is used in a motor, it has "Zero" radial clearance when an axial load is applied. If there is any radial clearance, vibration and noise of the balls will occur, and the stiffness of the ball bearing will be very low. This force that is applied in the axial direction is known as preload. An optimum preload should be individvally specified for each ball bearing size. If the Preload is applied excessively, Bearing Fatigue Life will be short and will increase raceway noise as well. Bearing starting and running torque will also be high. If the applied Preload is insufficient, fretting corrosion can occur. This happens as a result of vibration causing the balls to resonate and abrade on the raceways. Therefore, obtaining the correct Preload is very important.

Evan
01-03-2009, 12:10 PM
Evan. You might want to rethink the spindle nose. Just my 2 cents, but it looks like the perfect opportunity make a D type spindle, or any spidle type thaqt ian't threaded. I only mention it because of the tendancy for a threaded chuck to unwind when in reverse. The tendancy increases with the size of the chuck.


I have never had that happen except once when I was trying to unstick a large MT drill bit from some work in reverse. I machine in reverse all the time. When I made the backplates for my chucks back when I first got the lathe I made them a fairly snug fit on the register on the SB. They are tight enough that they will not spin on but must be wound on the last turn or so. I have cut the register on the new spindle the same way. I have also made provision for a friction area that engages the chuck back plate threads. I'll report on that perhaps at some later time. I can't afford to buy new chucks for this lathe at this time but I do have in mind to buy an 8 inch 4 jaw as a more or less permanent chuck on the lathe.

lazlo
01-03-2009, 12:30 PM
A Cam lock chuck would be cool (I wish I had that on my Clausing == L-00), but in your case Evan, I'd rather have a common mount with the South Bend, so you can move chucks back and forth between the two lathes.

John Stevenson
01-03-2009, 12:42 PM
That makes a lot of sense.
I did a dividing head some years ago that had a D1-3 on it so I could swap chucks with the lathe and they are not easy things to do unless you have a decent drawing, trying to measure converging holes off an existing spindle isn't easy.

You can always do what Myfords have done with their Conney sewer lathe and fit a safety device that won't allow it to screw off.
Quite simple really but a sketch would help, I'll do one later as I'm a bit tied up at the moment.

.

S_J_H
01-03-2009, 12:53 PM
Robert,
hmmm, I really don't know what to say if yours measures in at a .001 runout.
Hard to imagine a lathe being much use with .001" spindle runout, even if it's a mini lathe, but I'll take your word for it.

If I take a video showing a simple DI measuring the runout at the spindles OD would that help?

I have new SKF abec 3 bearings in one of the head stocks. Runout at the spindle OD is under .0002" I would say. Hard to be super precise as I have only .0005 DI's but it's pretty darn good.

take a look at this link, Testing a new Sieg c6 for runout. Well under .0002"!
http://www.mini-lathe.com/C6_lathe/C6/c6.htm

Steve

S_J_H
01-03-2009, 12:58 PM
another link testing a Sieg c4- you have to see the runout on this one as it's almost to good!
http://www.mini-lathe.com/m4/C4/c4.htm

Note he says he typically measures .0003-.0004 on the mini lathe which is exactly what I have seen.

lazlo
01-03-2009, 01:09 PM
I really don't know what to say if yours measures in at a .001 runout.

What about Gagetbuilder's 7x10? The Sieg test specs?


Hard to imagine a lathe being much use with .001" spindle runout, even if it's a mini lathe, but I'll take your word for it.

The 7x10 spindle runout just the half of it. On most mini-lathes, including mine, the tailstock is bored about 1 - 2 thou out of parallel with the lathe ways, so turning anything with the tailstock is going to have even more runout than the spindle.

That's why there's so many articles about re-machining the tailstock base, and why MickeyD had a mini-lathe tailstock in his VMC, and hit a spark plug :)

Milling the tailstock base to square it up (http://warhammer.mcc.virginia.edu/ty/7x10/vault/Members/RickKruger/Tailstock/BaseMod/MillingBase.html)

I have new SKF abec 3 bearings in one of the head stocks. Runout at the spindle OD is under .0002" I would say. Hard to be super precise as I have only .0005 DI's but it's pretty darn good.

Ah, now that explains a lot. You replaced the stock Chinese 6206 ball bearing in the 7x10 headstock with an SKF Explorer bearing, right? Those are effectively ABEC-5 bearings. I love those bearings -- MSC carries them, and they're 25% off...

I actually bought the SKF Explorer 30206 (tapered roller bearing) which is a drop-in replacement for the 7x10 deep groove ball bearing. A lot of guys do the tapered roller bearing upgrade, and it makes a huge improvement in the 7x10's runout:

http://www.arceurotrade.co.uk/projects/C3_BC/pages/index.html


take a look at this link, Testing a new Sieg c6 for runout. Well under .0002"!
http://www.mini-lathe.com/C6_lathe/C6/c6.htm

The C6 uses a (cough -- :)) preloaded tapered roller bearing, so I don't doubt that runout measurement. Although I found it amusing that he notes that his dial indicator is a "high quality Peacock indicator." I have a couple of those -- they're low-end Chinese indicators. Very sticky and rough movement.

John Stevenson
01-03-2009, 01:09 PM
Plus note he's testing the taper socket NOT spindle roundness.

I have about 3 or 4 C4 heads here that I'm working on plus a couple of spare spindles and I'm also seeing good results but then again it should pay off with their investment in the latest Swiss CNC grinders.

.

SDL
01-03-2009, 01:16 PM
I'm also seeing good results but then again it should pay off with their investment in the latest Swiss CNC grinders.

.

Should have told them to save the money and get a few South Bends:D:D

Steve Larner

J Tiers
01-03-2009, 01:20 PM
...............

S_J_H
01-03-2009, 01:21 PM
You replaced the stock Chinese 6206 ball bearing in the 7x10 headstock with an SKF Explorer bearing, right? Those are effectively ABEC-5 bearings. I love those bearings -- MSC carries them, and they're 25% off...

Yep that's what I bought.:) Glad to hear it's a good bearing.
Did make a big improvement over stock. As well as taking the time to redo the spindles rear bearing fit so preload is easier to adjust.

Well we probably spent enough time talking about Sieg lathes in Evans thread so we'll just have to say runout specs are not very consistent on those machines it seems.


I have about 3 or 4 C4 heads here that I'm working on plus a couple of spare spindles and I'm also seeing good results but then again it should pay off with their investment in the latest Swiss CNC grinders.

Very interesting!

lazlo
01-03-2009, 02:09 PM
Just quit bugging me, already, if you can't read...

The preload is AFTER the clearance is already taken up..... of course. Sheesh.

The preload is what takes up the clearance. Bearing preload doesn't happen afterwards.


Preload, by definition, removes the internal clearance of a bearing by wedging the inner and outer races.

Preloads
http://www.rotoprecision.ca/Products/Miniature_Bearings/Internal_Geometry.htm

Preloading is used to remove the internal clearance of a bearing and is achieved by applying a permanent thrust load in an axial direction.


Purpose for Preload
http://www.eminebea.com/content/html/en/engineering/bearings/preload.shtml

When a ball bearing is used in a motor, it has "Zero" radial clearance when an axial load is applied.


Why do you think that motors have a wave washer at one end? It's to preload the shaft against the bearings, and remove the radial play. :)

lazlo
01-03-2009, 02:22 PM
The preload is what takes up the clearance. Bearing preload doesn't happen afterwards.

By the way, I've got a couple of PM's asking about this, so here's a simpler explanation of bearing preload:

Go get a bearing -- any bearing, doesn't matter, but it's easier to see/feel on an open bearing (non sealed, non-shielded). Hold it by the outer race in one hand, and jiggle the inner race back and forth. That's the axial clearance ("play").

Now jiggle the inner race up and down. That the radial clearance. Even an ABEC-9 ultra-precision angular contact bearing with C1 internal clearance has that play, or the bearing wouldn't spin.

Now holding the bearing in one hand, push on the inner race with a finger from the same hand, and then try to jiggle the inner race with the other hand: congratulations, you've preloaded the bearing :D

There's only one problem: the inner race is now sticking out the side opposite you're pushing on, so it won't seat in a bearing pocket. So a "preloaded" bearing has the inner race ground short, by the amount of preload. If you grind the inner race short by 1 thou, you have a light preload bearing. When you stick it in the spindle, there's a bearing spacer that matches the preload offset on the bearing, and when you tighten it up, the outer and inner race are back to flat.

This is why machine spindles use pairs of preloaded bearings: the bearings are ground together so that when they're correctly preloaded, the inner races are pressing flat against each other, and both bearings are preloaded.

With a dual-row bearing like Evan used, there's effectively two bearings sharing a single inner race, so you can't wedge them against each other to preload them in face-to-face configuration like a machine spindle. You can still use a radial thrust to reduce the overall clearance, but not to the extent that you can with two seperate bearings.

Willy
01-03-2009, 02:26 PM
That makes a lot of sense.
I did a dividing head some years ago that had a D1-3 on it so I could swap chucks with the lathe and they are not easy things to do unless you have a decent drawing, trying to measure converging holes off an existing spindle isn't easy.

You can always do what Myfords have done with their Conney sewer lathe and fit a safety device that won't allow it to screw off.
Quite simple really but a sketch would help, I'll do one later as I'm a bit tied up at the moment.

.

John I posted this a while ago, but is this along the lines of what Myfords use for chuck retention?

http://i76.photobucket.com/albums/j31/250willy/chuckmount.jpg

Rustybolt
01-03-2009, 03:13 PM
Just a heads up Evan. It has happened to me on nearly every threaded spindle lathe I've run. Of course I have done a lot of production on those lathes. Very annoying when you have to keep rethreading the chuck every dozen or so pieces out of a hundred piece run,(threading 10-24 from a die in the tailstock) Whatever. It looks to be an exciting build, keep the pictures comming.

Evan
01-03-2009, 04:48 PM
Just a heads up Evan. It has happened to me on nearly every threaded spindle lathe I've run. Of course I have done a lot of production on those lathes. Very annoying when you have to keep rethreading the chuck every dozen or so pieces out of a hundred piece run,(threading 10-24 from a die in the tailstock) Whatever. It looks to be an exciting build, keep the pictures comming.

Well, don't anyone say I can't take some advice this time. I spent this morning working on the spindle and one thing I did was machine up a chuck lock.

http://metalshopborealis.ca/pics5/chucklok1.jpg

http://metalshopborealis.ca/pics5/chucklok2.jpg

It's easy enough to make sure the chuck won't come off if you slam it on the spindle. Of course, it may never come off if you do that. With the locking ring at 18 tpi I can jamb it tight enough it will be like the chuck was slammed on. Easy to remove later though.

John Stevenson
01-03-2009, 05:27 PM
Evan,

All this locking ring will do is to try to push the backplate off the register. I know you will argue until hell freezes over and yes it is cold up in Williams lake but a threaded spindle on the SB relies on the register diameter and back face to remain true

I have seen many Myford lathes who have the exact same mounting as the SB where the threads are worn to the extent that the chuck wobbles as it is screwed on but once mounted up on the register they retain their accuracy and repeatability.

All this ring will do is to attempt to unseat the rear face and a fine thread will do this better than a course thread.

.

aboard_epsilon
01-03-2009, 05:32 PM
Too bad you had to limit yourself with a spindle that takes south bend chucks

my biggest complaint on my lathe the 1024 smart and brown is its hole down the centre is too small.........

and this is a 5c hole.

so if I was building a lathe, hole centre is up there near priority number one.

This bearing is probably more purposeful .........its a wheel bearing off a Mercedes sprinter van ........couple of these and you could have a huge hole down the centre....

its the same as this ..



pic

http://img.photobucket.com/albums/v190/aboard_epsilon/catbearing.jpg

all the best.markJ

Evan
01-03-2009, 05:34 PM
All this locking ring will do is to try to push the backplate off the register


It won't though. That's why it is a jamb nut. I have considered that possibility anyway and if there is any sign that it somehow is able to unseat the chuck then the desired effect can be had by inserting a compliant washer between the lock nut and the back plate. As long as preload is maintained against the spindle threads then so is the friction that holds the chuck on.

JeffKranz
01-03-2009, 05:45 PM
Evan,

I always enjoy reading your post and am amazed on what you machine. The only think I don't really care for is all the BS from some people that want to give their opinions when you really are looking for them. I'm sure someone with your savvy could create a BLOG so we can follow your progress like reading a book and not trying to find the forest through the trees. I really like Bob Warfield's CNCCOOKBOOK blog since it is well done and you can follow the project without all the BS. It is not that these people don't have good point it is just they want to get more air time.

Just my opinion.

Jeff

John Stevenson
01-03-2009, 06:07 PM
This bearing is probably more purposeful .........its a wheel bearing off a Mercedes sprinter van ........couple of these and you could have a huge hole down the centre....

its the same as this ..



pic

http://img.photobucket.com/albums/v190/aboard_epsilon/catbearing.jpg

all the best.markJ

Mark,
Evans bearing is actually larger than that one but thanks for posting it as it clearly shows the split inner which is what I have been trying to explain all along as A BETTER ALTERNATIVE.


Evan,

I always enjoy reading your post and am amazed on what you machine. The only think I don't really care for is all the BS from some people that want to give their opinions when you really are looking for them. I'm sure someone with your savvy could create a BLOG so we can follow your progress like reading a book and not trying to find the forest through the trees. I really like Bob Warfield's CNCCOOKBOOK blog since it is well done and you can follow the project without all the BS. It is not that these people don't have good point it is just they want to get more air time.

Just my opinion.

Jeff

Jeff, Sorry if you think this is bullsh1t but it isn't, many people read these posts and there are many ways to do things, not just Evans and without offering alternatives then this forum just becomes one mans blog.

As regards air time, a lot of Evan's 22,343 posts have been earned arguing with others to get his point of view over.

.

Evan
01-03-2009, 06:34 PM
As regards air time, a lot of Evan's 22,343 posts have been earned arguing with others to get his point of view over

If you took all of those out I would still have a lot of posts. The discussions are not the majority and not even a large minority of my posts. I have posted a very large number of projects over the years. To give you an idea how many I currently have online some 3300 images the vast majority of which directly concern machining topics in some way. The arguments are rarely started by me and don't amount to more than a small part of my postings. I also answer a lot of questions that people ask. A lot has to do with the years when I was operating my computer store and was sat in front of a computer all day.


which is what I have been trying to explain all along as A BETTER ALTERNATIVE.


It isn't an alternative as I don't have one and am not buying one. I explained that in my first post.

BillH
01-03-2009, 06:39 PM
Mark,
Evans bearing is actually larger than that one but thanks for posting it as it clearly shows the split inner which is what I have been trying to explain all along as A BETTER ALTERNATIVE.



Jeff, Sorry if you think this is bullsh1t but it isn't, many people read these posts and there are many ways to do things, not just Evans and without offering alternatives then this forum just becomes one mans blog.

As regards air time, a lot of Evan's 22,343 posts have been earned arguing with others to get his point of view over.

.
Well I just want to comment that I hope Evan keeps on posting his projects and with all the great pictures despite how much he ends up arguing his points. I've learned a great deal from the posts.
Evan, you never went into detail on how you carefully machined the spindle, that in itself would be extremely interesting.

Evan
01-03-2009, 06:53 PM
Evan, you never went into detail on how you carefully machined the spindle, that in itself would be extremely interesting.

I realize that but I didn't grab the camera at the start when I should have. I did use a trick that I would guess most people don't know about to center up the work. Even using great care and a sharp center drill it can be difficult to produce an exactly centered center bore in the end of the work. As I was machining to some existing features and had to remove and replace the spindle a number of times I brought the right end of the spindle into center by shimming my live center with a bit of brass foil. The shim is cut from thin foil .001 thick by perhaps 30 thou wide and is slipped in along side the center point to bring the work in line if it is out. At all times when centering up the work I used as a maximum deviation allowable .0005" or plus/minus 0.00025" .

John Stevenson
01-03-2009, 06:57 PM
It isn't an alternative as I don't have one and am not buying one. I explained that in my first post.

Sigh,
But it would be to anyone who didn't have ANY bearing and had to buy or obtain one.

My replies are not just for your benefit.

.

BillH
01-03-2009, 06:57 PM
I realize that but I didn't grab the camera at the start when I should have. I did use a trick that I would guess most people don't know about to center up the work. Even using great care and a sharp center drill it can be difficult to produce an exactly centered center bore in the end of the work. As I was machining to some existing features and had to remove and replace the spindle a number of times I brought the right end of the spindle into center by shimming my live center with a bit of brass foil. The shim is cut from thin foil .001 thick by perhaps 30 thou wide and is slipped in along side the center point to bring the work in line if it is out. At all times when centering up the work I used as a maximum deviation allowable .0005" or plus/minus 0.00025" .
I figured it had to of been turned between centers for that. No way any of my lathes would hold .0005 from the chuck with that length of stock. Need to bolt the lathe down and level it.

John Stevenson
01-03-2009, 07:04 PM
I brought the right end of the spindle into center by shimming my live center with a bit of brass foil. The shim is cut from thin foil .001 thick by perhaps 30 thou wide and is slipped in along side the center point to bring the work in line if it is out. At all times when centering up the work I used as a maximum deviation allowable .0005" or plus/minus 0.00025" .
???????? you are machining to 2 and a tad micron on a 1939 flat belt South Bend and you have to shim the centre by 1 thou [ not 0.00098" ? ] to get these tolerances.

Sorry lads, fück it I'm outta here.

I've been out gunned, outwitted and out bullshîtted.

If you can believe all this bullshît you are welcome................

.

Evan
01-03-2009, 07:12 PM
you are machining to 2 and a tad micron on a 1939 flat belt South Bend and you have to shim the centre by 1 thou [ not 0.00098" ? ] to get these tolerances.


Never used that trick I see. The brass squishes and becomes thinner. [add] More to the point if the cente spot is off by a thou you need a thou to put it on.



But it would be to anyone who didn't have ANY bearing and had to buy or obtain one.

My replies are not just for your benefit.



Your replies were criticism of my choice of bearing. if your replies we not for my benefit then they sure as hell didn't help anybody else.



No split ring configuration so it's a preset. the preload adjuster you are building isn't a preload adjuster at all but just an end float adjuster.

Putting load on that adjuster will only put pressure on one set of bearings and reduce it from the other.

To use this double angular contact design correctly you need either a split race double angular contact bearing or two separate back to back bearings with the adjustment nut directly behind the bearings.

The way you have it you might as well just use one bearing.
Those double bearings is designed mainly for wheel bearings on cars that need maximum axial capacity, which as you posted in your first post is 8 tons, nearly equal to the radial load capacity of 10 tons.

Ideal for cornering loads but try any wheel bearing after a few 1,000 miles and it always has a little bit of shake, no problem on a car but image the surface finish if that were a lathe.



You totally ignored that I stated in front that this is what I will be using. Then you maintain it's just a "wheel bearing" that will wear out in short order as if my use could possibly load it enough to make it wear. Then you swear that the wheel bearing above is just the ticket.

And, you all but call me a liar in public about my measurements of the bearing and spindle runout. Get stuffed.

[edit]
Cross post. John doesn't like competition for the "big fish in the small pond" title. He began to realize this when I fired up my CNC mill. He thought I was a newbie to CNC and would have a long learning curve. I didn't.

Ken_Shea
01-03-2009, 07:28 PM
Sorry lads, fück it I'm outta here.
.

John, I usually get something out of your experiences and the resultant shared information, however, in this case, thank you for the above.

Not that you give a s__t is fully understood.

Ken

J Tiers
01-03-2009, 08:58 PM
......................

J Tiers
01-03-2009, 09:14 PM
It won't though. That's why it is a jamb nut. I have considered that possibility anyway and if there is any sign that it somehow is able to unseat the chuck then the desired effect can be had by inserting a compliant washer between the lock nut and the back plate. As long as preload is maintained against the spindle threads then so is the friction that holds the chuck on.

A jam nut CAN try to push the original nut off its surface, but I think in this case it is OK....

A regular jam nut goes under a nut (not on top as will be obvious shortly)....then when the actual nut is tightened, it pushes the jam nut off its seating on the threads but tightens the joint. The jam nut bearing is relieved, or even reversed.

if you reverse that order, the jam nut tightens the joint further and takes the load off the real nut, again relieving or even reversing the loading.

But in this case, when the chuck is screwed down, the chuck threads are bearing against the back side (headstock side) of the spindle threads.

When the jam nut is run up against it, the bearing does not change. It is still against the same side of the threads.

You DO rely on the original seating being tight enough to have taken up any obvious stretch and slop.... so that the jam nut partly relieves the force on the shoulder surface, but does not totally relieve it. To relieve it would require the spindle to stretch, which isn't the object.

If the jam nut had a different coarser thread vs the spindle nose, and same hand of thread, it would TIGHTEN if the chuck tried to unscrew. I don't know if that would be very practical for a 1 1/2-8 thread.

lazlo
01-03-2009, 09:18 PM
Jerry, you've got some kind of weird brain-lock going on, so this is my last post on the topic.



Preload, by definition, removes the internal clearance of a bearing by wedging the inner and outer races.
WRONG.

I posted this same explanation from three bearing engineering handbooks, and you refuse to believe it:

What is preload?
http://www.bardenbearings.com/PDF%20CD/PB11.PDF

Preloading is the removal of internal clearance in a bearing by applying a permanent thrust load to it.

Preloads
http://www.rotoprecision.ca/Products/Miniature_Bearings/Internal_Geometry.html

Preloading is used to remove the internal clearance of a bearing and is achieved by applying a permanent thrust load in an axial direction.

Purpose for Preload
http://www.eminebea.com/content/html/en/engineering/bearings/preload.shtml

When a ball bearing is used in a motor, it has "Zero" radial clearance when an axial load is applied.

NTN Bearing Handbook
http://www.ntnamerica.com/pdf/2200/brgclear.pdf

8.4 Preload

Normally, bearings are used with a slight internal clearance under operating conditions. However, in some applications, bearings are given an initial load; this means that the bearings’ internal clearance is negative before operation. This is called “preload” and is commonly applied to angular ball bearings and tapered roller bearings.

J Tiers
01-03-2009, 09:28 PM
......................

lazlo
01-03-2009, 09:32 PM
Robert, now you are just telling LIES.

Who's telling lies Jerry? This is the exact quote:

http://bbs.homeshopmachinist.net/showpost.php?p=405474&postcount=36



The reason you pre-load the two angular contact bearings on a machine spindle is to reduce axial and radial runout.

WRONG.

What is preload?
http://www.bardenbearings.com/PDF%20CD/PB11.PDF

Preloading is the removal of internal clearance in a bearing by applying a permanent thrust load to it.

Preloads
http://www.rotoprecision.ca/Products/Miniature_Bearings/Internal_Geometry.html

Preloading is used to remove the internal clearance of a bearing and is achieved by applying a permanent thrust load in an axial direction.

Purpose for Preload
http://www.eminebea.com/content/html/en/engineering/bearings/preload.shtml

When a ball bearing is used in a motor, it has "Zero" radial clearance when an axial load is applied.

NTN Bearing Handbook
http://www.ntnamerica.com/pdf/2200/brgclear.pdf

8.4 Preload

Normally, bearings are used with a slight internal clearance under operating conditions. However, in some applications, bearings are given an initial load; this means that the bearings’ internal clearance is negative before operation. This is called “preload” and is commonly applied to angular ball bearings and tapered roller bearings.

J Tiers
01-03-2009, 09:42 PM
...........................

lazlo
01-03-2009, 10:05 PM
Jerry, I don't know if you're having a bad day or what, but you're going around in circles.

Those explanations all say the same thing: bearing preload is axial thrust that you apply to a bearing to take up the internal clearance.

You see to be having difficulty with the concept that preload is used to take up the internal clearance, which you claim doesn't exist:


As far as clearance, it is ASSUMED that clearance is zero in any set-up system

In any event, you're in an Evan loop, so I'm signing off...

lane
01-03-2009, 10:06 PM
What is preload? Preloading is the removal
of internal clearance in a bearing by applying
a permanent thrust load to it.

Originally Posted by lazlo
The preload is what takes up the clearance. Bearing preload doesn't happen afterwards.

The key word here is REMOVAL = what takes up.
Sorry J Tiers Lazlo said it .

Now for any one I understand what yall are fussing about . Nothing really Just one persons way of doing something verses every one else's. But will some one explain Evans bearing to me . I saw the diagram and understand it but how are can you preload that bearing and if you can not what is it used for. IT must be factory preloaded. Because from the diagram it can not be preload in both directions so what is it good for.

Don`t let them get to you Evan. I know people that will not ask questions on this forum just because of things like this .They are afraid of being ridiculed. I would use what I had to and Dam the torpedoes full speed ahead. IF you read close I see most are just reading in what they want to see and hear and a lot of what is not said.
I understand entirely what you are building and why and can even see it in my mine and you have not even built it yet. Hurry up I want to see if I am reading your mine right I`m good at that.

And yes I went back out to the shop tonight and put my Starrett 4inch dia dial 1 tenth dial indicator on the register behind the threads on my 10K south bend and it does not move turning spindle by hand. Running 280 RPM the needle just shakes but does not move off a line . I do not know what a micron is are 3 of them But a tenth is good enough. I even put my 1/2 tenth indicator a Best Test and it did not move are shake . I do not know where but read one time that plain bearings were superior th ball bearings up to a point ,but would not handle the speed of ball bearings. Lane

dan s
01-03-2009, 10:14 PM
Jesus H Christ....

Would you menopausal ladies take your sniping contest to a new thread, and stop screwing up this one; some of us are actually interested in what Even's doing...

wierdscience
01-03-2009, 10:16 PM
This bearing is probably more purposeful .........its a wheel bearing off a Mercedes sprinter van ........couple of these and you could have a huge hole down the centre....

its the same as this ..



pic

http://img.photobucket.com/albums/v190/aboard_epsilon/catbearing.jpg

all the best.markJ

Mark,I have intimate knowledge of those units.Used them on several projects at work and home.

The preload as set by the factory is a bit loose for our uses.However all that needs to be done to change the preload is to pop the inner races out and dust off their inner faces on a surface grinder.

One could trial and error fit to the exact preload,or they could be dusted off by .002" each race and the spindle fitted with an adjustable preload nut.

The seals might become an issue if the RPM should ever climb above 800-1000,but they could be removed and the bore fitted with labrinth seals for oil lube.

lazlo
01-03-2009, 10:17 PM
I saw the diagram and understand it but how are can you preload that bearing and if you can not what is it used for. IT must be factory preloaded. Because from the diagram it can not be preload in both directions so what is it good for.

You're absolutely right Lane -- that's what John said on page 2 :)

Evan's using a Double-row angular contact bearing, which is essentially two angular contact bearings fused together, sharing a single inner race. So you can't duplex preload a double-row angular contact bearing like you can with a pair of angular contact bearings, as used in machine spindles.

Double-row angular contact bearings are used in pumps, AC compressors, and leadscrew drives, including the knee lift on a Bridgeport :)

http://www.tec.nsk.com/images/zu01_01e.gif

Double-row angular contact ball bearings are basically two single-row angular contact ball bearings mounted back-to-back except that they have only one inner ring and one outer ring, each having raceways. They can take axial loads in either direction.

Evan
01-03-2009, 10:20 PM
A jam nut CAN try to push the original nut off its surface, but I think in this case it is OK....



As I said, it will increase the friction on the threads. There is no way on Earth that it will be able to compress the chuck back plate against the spindle nose threads enough to relieve contact on the register. It won't even come close. I did consider making it 6 tpi stub acme but even then the depth of thread was more than I wanted to cut. Considering that I haven't had chuck unscrewing problems this is more a belt and suspenders approach. I will probably be putting on a 3 phase motor with VFD so soft start will help even more to prevent chuck problems.


I am seriously considering posting the rest of the build info on my own site. I may even fire up the forum software so that questions and general discussion may take place. If I do there will be one rule. Everyone must be civil. Nobody will be banned but posts may be deleted if they are abusive.

Maybe. I haven't yet decided but I have unlimited bandwidth and file space.

lane
01-03-2009, 10:27 PM
I get what you are saying . So how does it work . Pushing one way must take thrust are load . then pushing other way must do the same. But why would have thrust first from one way then another . So if Evan tighten it up he is only using one set of the balls Which is still ok. All it amounts to is he got more bearing than he needs. But again its all he had that was big enough in ID and OD . Ok that explains it. I think. I got it he is going to put a chuck on both ends with the head stock in the middle of the lathe bed.

Evan
01-03-2009, 10:28 PM
Robert, the picture you posted is not the configuration of the bearing I am using.

The 5310 is configured as a back to back pair of angular contact bearings that share the same races. It is internally preloaded and the contact angles diverge in the direction of the shaft making the bearing very rigid. This is ideal for a spindle nose bearing except that it cannot be adjusted the same as separate bearings can.

The config is like this if you didn't see it earlier in the thread.

http://metalshopborealis.ca/pics5/5310.jpg

J Tiers
01-03-2009, 10:29 PM
........................

lazlo
01-03-2009, 10:35 PM
Robert, the picture you posted is not the configuration of the bearing I am using.

The 5310 is configured as a back to back pair of angular contact bearings that share the same races.

That was just a generic picture from NTN showing a double-row angular contact bearing. This is the profile of the 5310 that you're using -- at little easier to see/visual the shared race:

http://www.dpibearings.com/index_files/image13751.gif

Someone probably knows off the top of their head, but I think the 5300 is the bearing in the Bridgeport knee.
Edit: yep, the Bridgeport knee uses the 5306 bearing -- the 30 mm ID version of Evan's bearing.

By the way, look at the dynamic load rating of that bearing: 88,000 Newtwons is 20,000 lbs. I don't think you're going to have load issues Evan :D

lane
01-03-2009, 10:47 PM
I follow what you are saying J Tiers. but at that point you are just squishing the balls in to the races to some extent . Take a wheel bearing on a car tighten it up to take the shake out the give the nut 2 more turns . The bearing aint going to last long. Not to say there may be some mfg .specs for some applications to some extent of tightness. but do not think that is a concern here.

Evan
01-03-2009, 10:50 PM
Leave me out of your argument Jerry.

Evan
01-03-2009, 11:01 PM
The image you are showing Robert is a twin row deep groove bearing. Note the outer race compared to this image from SKF. The bearing I have is from SKF.

http://metalshopborealis.ca/pics5/skf.jpg

J Tiers
01-03-2009, 11:02 PM
I follow what you are saying J Tiers. but at that point you are just squishing the balls in to the races to some extent . Take a wheel bearing on a car tighten it up to take the shake out the give the nut 2 more turns . The bearing aint going to last long. Not to say there may be some mfg .specs for some applications to some extent of tightness. but do not think that is a concern here.

Apparently they think it a good idea.... It will be what is going on internal to Evan's bearing as well, which should remove some of the issues that have been brought up to argue with him and his techniques, choice of bearing etc.

here is the relevant part of the book, hopefully made bigger. They are talking about a larger and more heavy-duty bearing, but the same exact thing comes into it at lesser forces for more delicate bearings.

The lifetime is a concern, but the actual preload would be well within the bearing load rating, might be a few percent only..... all depends on what the machine designer intends the bearing to carry in the application. Bearings last longer under less load.

Edit: I see photobucket is reducing the pictures to a small size only........ I'll try to get them bigger and easier to read.

Still not working....... I set them to be 800x600.....oh well...I can't get them to display any bigger, no matter what I set at photobucket. naturally I can see them fine over there at PB...... full size....

Hey, today they are at full size.... it's magic
http://img.photobucket.com/albums/0803/jstanley/pre1.jpg
http://img.photobucket.com/albums/0803/jstanley/pre2.jpg
http://img.photobucket.com/albums/0803/jstanley/pre3.jpg
http://img.photobucket.com/albums/0803/jstanley/pre4.jpg

lazlo
01-03-2009, 11:18 PM
The image you are showing Robert is a twin row deep groove bearing.

Evan, look at the title of the picture -- that's a standard 5300 series double-row angular contact bearing.

I'm not seeing the difference in the pictures between the shared bearing race? Do you mean the contact angle is different? The 5300 series is all 30° contact angle, face-to-face mount.

This is the SKF 5310 diagram -- looks the same as the other one I posted?

http://www.skf.com/skf/productcatalogue/servlet/productImage?prodid=125007410&imperial=false&lang=en

J Tiers
01-03-2009, 11:19 PM
Leave me out of your argument Jerry.

Let the galled jade wince?

Evan
01-03-2009, 11:31 PM
This is the SKF 5310 diagram -- looks the same as the other one I posted?



Not to me. The outer race is not a pair of grooves in the SKF bearing. That is a major difference as the bearings are free to move away from the central race projection on either side if unloaded, same as an actual pair of angular contact bearings.

It also isn't face to face. It's back to back according to SKF.

JRouche
01-03-2009, 11:53 PM
Oh man!!!! What a shame. I have been away, other pursuits, and when I last looked here there was more bickering than constructive talk. Same ol place.

Evan, great idea. New year, new machine. I loved your mill build up, that was enjoyable to read and watch.

Too bad there wasnt a thread lock function where a "build thread" could only be updated by the original poster to update the build progress. Would make it so much easier to view the build.

As it is now there is four pages of bearing talk. Cant imagine whats gonna happen when you show your bed ideas. Oh man!!!

I wonder how many folks here hesitate to post there projects for fear of all the arm chair quarterbacking. Not every project is gonna be a perfect match for everyones tastes. But they are ALL interesting. For someone like me who enjoys the skills presented.

Evan, keep up the great build. It will work just fine. I for one completely understand the build from the shelf mentality. I do it as much as possible. THATS HSM.... JR

J Tiers
01-03-2009, 11:53 PM
Not to me. The outer race is not a pair of grooves in the SKF bearing. That is a major difference as the bearings are free to move away from the central race projection on either side if unloaded, same as an actual pair of angular contact bearings.

It also isn't face to face. It's back to back according to SKF.

Evan: Their image is NOT representative of the title....... They DO mean angular contact, and that cannot be ordinary bearings which is what they actually show in the little image..... obviously poor editing.

There is an obvious question as to whether back-to-back etc has relevance in a one-piece dual row part.

But since the 5310 is a member of the series lazlo shows, and that second image of the part shows YOUR geometry, it looks as if the basic type is similar, although it may be of a different size.



Evan, keep up the great build. It will work just fine. I for one completely understand the build from the shelf mentality. I do it as much as possible. THATS HSM.... JR

+100

As long as the shortcomings of the 'available" parts are accepted, it works great. Most people are willing to accept that.

I dunno if I'd post the grinding spindle I am working on.... probably get the same treatment.

quasi
01-04-2009, 12:43 AM
the way Evan is being treated here, and the accompanying high jacking is why I hesitate to post any projects here.

barts
01-04-2009, 12:45 AM
... Cant imagine whats gonna happen when you show your bed ideas. Oh man!!!

I wonder how many folks here hesitate to post there projects for fear of all the arm chair quarterbacking. Not every project is gonna be a perfect match for everyones tastes. But they are ALL interesting. For someone like me who enjoys the skills presented ...

hear hear....

I shared my idea of how to make a steam engine from a compressor at a steamboat meet back in the mid 80s... lots of folks said it wouldn't work. I got it done and brought it to another meet; there was were several who felt it couldn't work in a boat. A year or two later I brought the completed boat, and gave the skeptics rides... some of them still don't have boats :p

- Bart

J Tiers
01-04-2009, 12:51 AM
....................

BillH
01-04-2009, 12:57 AM
Yes, guilty as charged....... I think the original input was relevant, but it spun off into a crazy la-la land.... At least ALL the arguing, both Evan vs JS and the rest of it was about bearings, and at least tenuously and nominally topical....... that isn't always true.

I dunno if there is an effective way to shunt such stuff aside.... I've seen it tried, but the junk stays in the first thread.... many don't bother to go to the new one.
Nothing new :)

lugnut
01-04-2009, 01:09 AM
Torker just got a new forum section going about welding,, Now I guess we need one for Lazlo and JTiers to see who can Piss the highest on the wall:D this kind of BULL is what is going to kill this forum if not pulled under control.
Mel

J Tiers
01-04-2009, 01:23 AM
................

MickeyD
01-04-2009, 01:47 AM
I don't think that this is about being right or wrong, I think this is about is it going to actually work. I went through something similar to this with my dad on the multimachine project (lathe made with old engine blocks) and he ended up going with tapered roller bearings for the spindle. In his case they were domestic automotive wheel spindle bearings (not the junky autozone ones, but domestic bearings from NAPA), and by swapping them around, buying extras and taking the ones back that were really sloppy, he got the spindle runout under .001" (the best that we could measure at the time). I know that Evan can do better than that, the work that he turns out on his SB9 is simply beautiful and shows an amazing attention to detail.

Another thing that I would seriously look at it using a spindle that is that small on a big swing lathe. From past experience I think that you are going to have enough flex in the spindle to cause chatter when you try to turn larger parts. The spindle on my 15" Colchester is about 3" in diameter and it is not considered a particularly heavy lathe.

BobWarfield
01-04-2009, 02:28 AM
Every now and then I come back looking around, hoping things have changed. Of course they haven't. If anything, they are worse.

I don't post projects here any more. It's a pity grown ups can't act a little more grown up.

Evan, looking forward to seeing your progress, whether it is documented here or on your personal site.

Sincerely,

BW

dp
01-04-2009, 03:11 AM
Too bad there wasnt a thread lock function where a "build thread" could only be updated by the original poster to update the build progress. Would make it so much easier to view the build.

The BBS software I run allows users to lock threads they start. I'd be surprised if VBulletin didn't. I think it is appropriate for a Projects forum, and for tutorial type content. Unfortunately, in the software I use (SMF) it is a global option so applies to all forums.

Evan
01-04-2009, 03:34 AM
Another thing that I would seriously look at it using a spindle that is that small on a big swing lathe. From past experience I think that you are going to have enough flex in the spindle to cause chatter when you try to turn larger parts. The spindle on my 15" Colchester is about 3" in diameter and it is not considered a particularly heavy lathe.

I'm not building a big lathe. I am building a little lathe with a big swing. I considered jacking up my SB but decided that I would be better off with two work lathes. I need to turn large diameter work from time to time. For instance, my telescope design was constrained by the size of the SB9 lathe.

http://metalshopborealis.ca/pics5/scope1a.jpg

The rings are exactly 9 inches outside diameter. If I had the capability when I built it I would have made it an 8 inch scope instead of a 6 inch scope. I don't have a need to turn large heavy parts, just large parts. Putting the centerline higher above the bed in no way makes the lathe somehow weaker or stronger for that matter. As long as it is properly designed it will work fine.


I really don't understand all the fuss about this bearing. It is a preloaded bearing with ten times the capacity it needs to have. It is completely rigid with no axial or radial play. Because it is so wide and rigid it will provide a much greater degree of support to the spindle nose than would normally be the case. The spindle at that point is 2" OD. You could cut off the rest on the other side of the nose bearing and it would still work. The bearing is a heavy temperature assisted press fit on the shaft. That is a part of the preload.

The bearing will work. There are plenty of usable lathes that have far less in the way of spindle bearings.

All my working life nearly every single job I have had, and there have been many in the early years, every job has had something to do with machines. Either building or maintaining, repairing or operating them and even designing them.

In fact, everything I build is my design. Even as a child I designed my own toys, games and models and built them. I have been designing machines since I was about 5 years old. It's what I like to do more than anything else. I like machines and the principles of operation that underlie everything we invent and exploit.

Davek0974
01-04-2009, 05:03 AM
Nice looking 'scope Evan, i can understand why you need to turn large but lightweight parts.

I am saddened by the state of this thread, i can see maybe 1-2 pages of worthwhile stuff and 12 pages of deep in-depth analysis of a bearing! I dont recall you asking for someone to pull your project apart, if you feel that your design will work (and i am sure it will in this instance) then why the need for it to be redesigned by others?

It would be ggod to be able to lock your own threads here, as it is a better site than PM due to its current interface difficulties and i view this s ite more often. !6 pages of comments on a project build - wow!

It certainly puts me off wanting to post pics of projects.

Dave

noah katz
01-04-2009, 06:41 AM
"Putting the centerline higher above the bed in no way makes the lathe somehow weaker or stronger for that matter."

Not that it's quantitatively significant in your application, but increasing the centerline height lengthens the moment arm of the forces, increasing stress and deflection in all of the machine structure in the load path between work and cutter.

aboard_epsilon
01-04-2009, 06:57 AM
http://img.alibaba.com/photo/205439325/catalogue_3_of_wheel_hub_bearing.jpg

all the best.markj

John Stevenson
01-04-2009, 08:37 AM
OK one last post before we leave it to Evan seeing as I was probably the one who derailed the post, which wasn't my intention.

Some points first that have already been covered in the post. This 5310 bearing is a double row angular contact with no adjustable preload other than manufacture and assembly.

They are designed for loads where the thrust is from both sides, wheel bearings and as Lazlo has said the knee on a Bridgeport which is presented with loads from two directions, ie. wind up, wind down.

A lathe doesn't have these opposing forces resulting in one race doing next to nothing.

Will it work in Evan's case ? Sure it will and work well given the bearing size and the loading.
From one table published it has a loading of nearly 82,000 Newtons [ it's the sealed bearing with a lesser loading ] more than enough.

A single row angular contact bearing of the same ID / OD has a loading of 76,000 Newtons. So the bearing manufactures accept that one race is doing very little hence only 6,000 Newtons difference.

I whole heartedly accept that this will work for what Evan wants it to do, hell even one deep groove has a loading of 64,5000 Newtons and it's heavy duty mate is rated at a whopping 84,500 Newtons.
I also accept that Evan used this as it was available for free, and that rates high up on the list.

My mistake was to point out to people following the thread that it wasn't the best choice. Looking at the data above just one angular contact bearing with an ordinary ball race at the back, or even a second angular contact would give or exceed the specs of this bearing.

After that I was told by Evan why it would do what the manufactures say it will not do by design.

In typical Evan fashion he then twisted words, ignored questions and even posted the Nachi link which disproved his theory.

Spin Doctor who worked on high speed spindles all his life even came to my rescue and was ignored, so much for experience.

My post # 37 basically says the same as this post.

This all isn't aimed at Evan, it might look that way after it got out of hand. There isn't a right and wrong way to do many things in this trade there are just many ways and if people can't see that then they are either thick or blinded by their own importance.

I don't know everything that's why I come here, I learn a lot. I learn a lot from Evan as I know sod all about many subjects but I do know there are alternative ways to do most things.

So basically this is a tongue in cheek apology, not to Evan as I don't feel I have slighted him, his bearing WILL work, but to the rest of the readers on this forum for allowing the thread to run away.

.

Evan
01-04-2009, 09:05 AM
his bearing WILL work,

That's the part you failed to mention at the outset John. It would have gone a long way if you had.

John Stevenson
01-04-2009, 09:22 AM
That's the part you failed to mention at the outset John. It would have gone a long way if you had.

I did but it took me until post # 37 :D

.

dhammer
01-04-2009, 09:33 AM
[So basically this is a tongue in cheek apology, not to Evan as I don't feel I have slighted him, his bearing WILL work, but to the rest of the readers on this forum for allowing the thread to run away.

.[/QUOTE]
I don't think an apology to the "rest of the readers" is needed. I, for one, enjoy spirited discussions. Is that not the scientific method? State your position, back it with evidence and argue back and forth..supposedly that is how we all can come to the best conclusions.

There is a lot to be learned from this forum, egos often cloud the issues but that is often the case with people who are good at what they do.

Peter.
01-04-2009, 09:54 AM
I've learned a lot from the thread that I never knew a thing about, so there have been some benefits for me at least. On the whole it's been a mostly technical discussion without descending too far into personal ego-bashing. Some points a bit too heavily-laboured and dragged-over but on the whole a discussion with many merits I think.

Evan
01-04-2009, 10:01 AM
I'll be posting further progress in a new thread for now. This one is too deep to wade through. We'll see how it goes.

John, the way you came across to me is that you were slamming my choice of bearing even though it wasn't a choice. You didn't allow the possibility that it would serve until it was too late. That wasn't the only issue though. It really gets me steamed when somebody implies that I am lying. The measurements I made are real and I took care in making them.

You may have noticed my setup. There is a small cast iron table that is keyed to the ways by underside vee grooves. A large lead weight holds it in place and provides damping. The mag base clamps directly to the table and the indicator is mounted as close as possible to the base to minimize deflection in the support. Without such measures it isn't possible to obtain reliable readings in that range.

torker
01-04-2009, 10:11 AM
Holy Smoke! What a wild runaway happened here...
Ummm..."this will kill the board"...lol!
How many times have I heard that..and it's still here.
I am sorry to hear from a couple of respected members here that they no longer post their projects on here.

I post a lot of my "Rube" inventions on here. I do it with an open mind.
Yup...I think my way is the best...or I'd buy what i needed from Crappy Tire.
I've been sorta disappointed a few times that my genius wasn't recognized :D
That my idea wasn't the BEST way...
So I just tell myself..."Sukk it up Princess and learn from those who actually know the subject".

We seem to be a large collection of open minded thinkers here.
We don't need the "See the plans".
We already saw the plans...in our heads.
Sometimes our plans need adjustment.
Sometimes....it turns out we are right no matter what the experts say...
Russ

ptjw7uk
01-04-2009, 10:46 AM
Oh what a shambles, I think a lot of people on this forum read a post and miss bits they dont like the sound off and seem to go straight for the jugular. As Evan said in his first post it was what he had to hand as is most of what Torker does( keep it up, I really like your escapades into the unknown) and to me this is what this forum is all about. I enjoy reading of peoples trilas and tribulations into areas I can only dream off in that I lack the space and materials to try most of the 'goodies' people endeaver to make.
I am really sorry that Bob Warfield has felt it necessary to curtail his contributions still his web site is always worth a visit.
Please keep posting I for one welcome the effort, I also occasionally like to read the correct way of doing things but as a philistine in these matters I always think needs must and often resort to none 'correct' methods.

Anyway Happy New Year anyway

Peter

J Tiers
01-04-2009, 11:00 AM
I think even the JS apology (assuming one was needed) is a bit unfair.

The double-row bearing, assuming it is indeed internally preloaded, will be a stiff locator for the spindle in all axes (after obviously first eliminating clearances lazlo), and accurately position the spindle relative to the machine if the outer housing is held well. Then a tail bearing, which Evan has provided, will hold the rest of the spindle. It is fairly standard, according to what I have seen in the bearing manuals and in machines.

It is EXACTLY EQUIVALENT to a pair of opposed angular contact bearings located at the spindle nose, IF it is internally preloaded.

Contrary to the assertion that it is somewhat useless because one bearing is unloaded, this is exactly the same situation that would occur if there were two opposed angular contact bearings.

And if it IS preloaded,the pressure against the front one would PARTIALLY unload the rear, but mot entirely. That is the key issue with preload. EVEN WITH pressure on the front bearing, enough preload remains to prevent the rear bearing from being unloaded, which might allow that part to 'flop around" unguided with the clearances in full play.

That is more important with bearings at each end of a long spindle than when the bearings are closely located together as in this case. But I believe you will find lots of lathe spindle assemblies made just the same as Evan's design, but using opposed separate bearings, which are preloaded externally. Just go through the UK machine tool archive..... many of the spibndle assemblies are shown and explained there.

And, the construction Evan is building is essentially EXACTLY the construction of the original Logan lathe spindle. When an OEM internally preloaded bearing is used, that system works very well indeed.

The only quarrel is whether the actual bearing runout etc is adequate to make a credible lathe spindle. if Evan's measurements are accurate, it is.

Now, I have only Evan's statements for the facts on the bearing (and pictures), but I have no reason to assume they are not accurate.

I suppose this will go as totally ignored, but that won't change the facts..........




Some points first that have already been covered in the post. This 5310 bearing is a double row angular contact with no adjustable preload other than manufacture and assembly.

They are designed for loads where the thrust is from both sides, wheel bearings and as Lazlo has said the knee on a Bridgeport which is presented with loads from two directions, ie. wind up, wind down.

A lathe doesn't have these opposing forces resulting in one race doing next to nothing.

Will it work in Evan's case ? Sure it will and work well given the bearing size and the loading.

My mistake was to point out to people following the thread that it wasn't the best choice. Looking at the data above just one angular contact bearing with an ordinary ball race at the back, or even a second angular contact would give or exceed the specs of this bearing.

Spin Doctor who worked on high speed spindles all his life even came to my rescue and was ignored, so much for experience.

.

John Stevenson
01-04-2009, 11:13 AM
It is EXACTLY EQUIVALENT to a pair of opposed angular contact bearings located at the spindle nose, IF it is internally preloaded.

Contrary to the assertion that it is somewhat useless because one bearing is unloaded, this is exactly the same situation that would occur if there were two opposed angular contact bearings.



Only if it is internally pre loaded to the correct amount.
Now this bearing is a generic off the shelf bearing that comes under tight manufacturing tolerances but even then there ARE tolerances.

From the NSK book [ I can scan it if no one believes me], it quotes from zero, min to 25,max. these units are in 0.001mm units so depending on whether it's a Monday bearing or a Friday bearing :D it can be from zero to 0.025mm axial play.

With two opposed bearings this axial play can be shimmed out, not so with the double row so you are basically back to running on one race as I said previously.

Long short is these are not designed for preloading but as a bearing that takes two opposed loads.

O and by the way it will still work in Evans spindle :D

.

J Tiers
01-04-2009, 11:19 AM
Only if it is internally pre loaded to the correct amount.

.

Absolutely and I do agree. If the preload is very light it is equal to no preload at all for practical purposes.... or I suppose with wide enough tolerances it might BE no preload ;)

yes, it would be good to see the spec. I didn't recall seeing a manufacturer or number for the actual bearing, so I never tried to find it.

torker
01-04-2009, 12:23 PM
What kind of earth shattering thing would happen if you threaded the rear part of the spindle and added some preload to those bearings?

Evan
01-04-2009, 12:29 PM
What kind of earth shattering thing would happen if you threaded the rear part of the spindle and added some preload to those bearings?


I did Russ. :D

J Tiers
01-04-2009, 12:32 PM
Not only that, but as the bearing is supposedly internally preloaded, it wouldn't make a particle of difference.

Unless of course, the internal preload is very little, or non-existent.

John Stevenson
01-04-2009, 12:32 PM
It's the cold, he's not awake yet :D

.

John Stevenson
01-04-2009, 12:37 PM
Not only that, but as the bearing is supposedly internally preloaded, it wouldn't make a particle of difference.

Unless of course, the internal preload is very little, or non-existent.

Yes it would and this is what i have been saying all along, if you preload it with a pull nut as Evan is doing, in a worst case scenario with max axial play it will pull it back onto the first race and take load off the rear race.

That is why the double row has a rating of 82,000 newtons but just a single row on it's own has a rating of 76,500, a scant 5,500 short.

So basically this double row is only working as a single row.

Oh and BTW Evan's bearing will work :D

.

J Tiers
01-04-2009, 12:49 PM
Yes it would and this is what i have been saying all along, if you preload it with a pull nut as Evan is doing, in a worst case scenario with max axial play it will pull it back onto the first race and take load off the rear race.

That is why the double row has a rating of 82,000 newtons but just a single row on it's own has a rating of 76,500, a scant 5,500 short.

So basically this double row is only working as a single row.

.

Well, if it were a double row with both oriented the same (not opposed), I would see your point.

But if it is internally preloaded and opposed, then an external "preload" would just add load to the front bearing and release it from the rear..... same as any thrust load, no real net gain.

of course, as an opposed, only ONE bearing is opposing thrust on the spindle nose, but the preload is still active to center it and reduce deflection. Pretty much equal to having a nut and so forth "inside' the bearing, unless the bearing in question does not HAVE internal preload, in which case you have to supply it outside, and THEN as you say, the rear bearing is not helping.

You posted a picture of a spindle bac a few pages, with a short double (separate) bearing set at the nose, and the spindle going off to the left somewhere.

if Evan's bearing is internally preloaded as he says, it should be equivalent to that (aside from bearing class etc...). If not, why not?

Not sure what you are trying to say that is different from what I said..

Do you have that spec you mentioned on Evan's bearing? It would directly clarify if that bearing actually IS internally preloaded...... and all this chatter would be settled right away.

wierdscience
01-04-2009, 12:54 PM
Wonder what the radial and axial clearances are in these bearings?:)

http://img.photobucket.com/albums/0903/wierdscience/5a.png

J Tiers
01-04-2009, 12:59 PM
Wonder what the radial and axial clearances are in these bearings?:)

Oil and plain bearings?

pretty good when running, radial around 1 thou when not.... S-B spec with 50 lb force on spindle, not running. IIRC 0.0007 to 0.0013

Evan
01-04-2009, 01:03 PM
I can't easily present the data here because it is in the form of a selection wizard but the SKF spec on the 5310 bearing's internal clearance is max zero microns/ min -12 microns. Assuming they hit the middle of the tolerance band they are shooting for a inbuilt preload of -6 microns interference fit.

Here it is:

http://metalshopborealis.ca/pics5/5310fit.jpg

J Tiers
01-04-2009, 01:50 PM
Ah, if that is the spec for yours, then there COULD be 'zero" interference which would be a total lack of preload. It would be "just enough" to take up the clearances... but any external load would develop a clearance on the rear bearing section.

That is sufficient reason to add external preload capability. You might want to consider using belleville washers, which are available from MSC here in many sizes for exactly that purpose, there must be a Canadian source like them.

The obvious advantage is relative heat insensitivity, despite expansions etc the preload force remains what you set it to.

I see from that spec what JS is saying... but of course you HAVE that bearing, and as has been mentioned, that counts for a lot when building your own stuff. You always have the ability to accept a less-than-perfect-for-the-use item.

John Stevenson
01-04-2009, 03:05 PM
I can't easily present the data here because it is in the form of a selection wizard but the SKF spec on the 5310 bearing's internal clearance is max zero microns/ min -12 microns. Assuming they hit the middle of the tolerance band they are shooting for a inbuilt preload of -6 microns interference fit.

Here it is:

http://metalshopborealis.ca/pics5/5310fit.jpg
?? No.
There is no axial tolerance on that page, the 0 to -12 is the tolerance on the bearing bore.

What you have to realise is the the bearing number in Evan's case 5310 isn't a bearing but a class of bearing all sharing the same generic ID, OD and width.

Just as say a standard bearing we all know and love say a 6203, just as an example, is a generic 17mm bore x 40mm OD by 12mm wide.
This same number also covers all the specials. Some are easily recognisable like 2ZZ and 2RS for two metal shields and two rubber seals but there is usually two pages of other specials per family. Like A*/* for special axial clearances.
Graded from C2 to C5
E for extra load capacity
R*/* for special radial clearances.

Sniped the last bit as it was incorrect, now found the actual info
.

John Stevenson
01-04-2009, 03:35 PM
Had to edit the last post as SKF's website made the 5310 obsolete and gave the specs for the newer 33 series which is a 25 degree contact angle which is no good as they have even greater clearances.

I had had to revert to an NSK design book as they still list the clearances for Evans bearing and it's unfair to list specs for a 25 degree bearing when he has a different bearing.

I wonder if this is where the problem arose with the Logan's, fitting a newer bearing to replace an obsolete one ?

Any NSK calls Evans bearing one of 3 specs, LDJK, MDJK and HDJK [ light duty, medium duty or heavy duty. This is the one with solid inner and solid outer.

There is another series called LDJT and MDJT with a split outer.

http://www.stevenson-engineers.co.uk/files/skf1.jpg

The pictures on on the right side, Evans bearing is the middle one.
On the left are the axial clearances.
Evans is from 0 to 25 as I stated before, the split outer which can be preloaded is from -25 to 0 making this an ideal bearing.

In the lower tables the 33 series all have high axial clearances and should be avoided for spindle work.

.

lazlo
01-04-2009, 05:43 PM
?? No.
There is no axial tolerance on that page, the 0 to -12 is the tolerance on the bearing bore.

Right. If you look at Evan's worksheet, the clearance button he checked is CLN, which means normal internal clearance. C1 or C2 would be less than normal internal clearance, and C3 would be more than normal clearance.

The internal clearance numbers are always positive, until you apply preload.

J Tiers
01-04-2009, 05:55 PM
I wonder if this is where the problem arose with the Logan's, fitting a newer bearing to replace an obsolete one ?



yes, I don't think they appreciated the difference until after they sold quite a few replacements.

lazlo
01-04-2009, 06:05 PM
John, the 5300 series is not obsolete. Go the the SKF product explorer, type in "5310" (Evan's bearing) and you'll get a dozen hits:

http://www.skf.com/skf/productcatalogue/Forwarder?newlink=&action=search&lange-en&prodid=124020310

Here's SKF's axial clearance sheet for the 5300 series. The standard internal clearance for a 5310 bearing is 11 - 33 microns. 33 microns is 0.0013":

Double row angular contact ball bearings

Internal clearance

SKF double row angular contact ball bearings identified by a series designation are produced as standard with Normal axial internal clearance. They are also available with the greater C3 clearance (matrix 1). Values for the clearance limits are given in table 1. For bearings with smaller C2 clearance, please check availability before ordering.

http://i164.photobucket.com/albums/u15/rtgeorge_album/SKF5300AxialInternalClearance.gif

John Stevenson
01-04-2009, 06:05 PM
Right. If you look at Evan's worksheet, the clearance button he checked is CLN, which means normal internal clearance. C1 or C2 would be less than normal internal clearance, and C3 would be more than normal clearance.

The internal clearance numbers are always positive, until you apply preload.
True, but until Evan states what is on the bearing, if anything, then it has to be taken as a normal bearing they do make a higher tolerance class of B4 and B6 according to the SKF book but don't publish the specs, the NSK book lists the CN as normal, the C2 as less axial clearance than normal but C3 and C4 are greater.

That page still only gives the mounting tolerances not radial tolerances.

Lazlo,
No that page is incorrect. that's the page I found, posted, then edited it out because you click on 5310 and then tolerances, you get the page you posted but look under the picture of the bearing.
It's the table for the 3300 series which is a 25 degree angle bearing.

Skef's web site leaves a lot to be desired and the book I have isn't much better, there is better info in the NSK book .

lazlo
01-04-2009, 06:13 PM
the NSK book lists the CN as normal, the C2 as less axial clearance than normal but C3 and C4 are greater.

The internal clearance specs (CN, C1, C3, etc) are AFMBA (bearing manufacturer) standards.


That page still only gives the mounting tolerances not radial tolerances.

I posted SKF's axial clearance table for their 5300 bearings above.

lazlo
01-04-2009, 06:16 PM
Lazlo,
No that page is incorrect. that's the page I found, posted, then edited it out because you click on 5310 and then tolerances, you get the page you posted but look under the picture of the bearing.

It's not wrong :) If you read the text on SKF's product page, that whole series of double-row angular contact bearings has the same internal clearance:

http://www.skf.com/portal/skf/home/products?maincatalogue=1&lang=en&newlink=1_3_27

The only ones that have different internal clearance are the split ring types like Epsilon posted, where they're preloaded, so they have a different table.

In any event, we're boring the folks who just want to see pretty pictures, so I'm off to the shop...

John Stevenson
01-04-2009, 06:34 PM
Well those tolerances are sh!t.
See my pic of the NSK book it lists two tolerances for the 30 degree bearing [ Evans bearing ] depending on whether it's split or not, thats the LDJK and the LDJT etc and under that is the 3200 / 3300 series [ 25 degree ] with the same massive clearances as the skef page.

This is the relevenat page from the NSK book
http://www.stevenson-engineers.co.uk/files/skf2.jpg

You can see it list the MDJK and the MDJT in Evans size as well as the 25 degree 3310B interesting the the MD and HD have a 21,000 newton difference for the same physical size.

The SKF book only lists one bearing to 3310B.

Perhaps I need to locate an older SKF book ?

.

Evan
01-04-2009, 07:52 PM
It's an old bearing maybe 20 years or more. They don't make the same bearing any more although they still use the same part number. I don't think the specs are available. The nomenclature on the bearing has changed also and they don't actually list the exact same bearing. I gave the number in the original post.

John Stevenson
01-04-2009, 08:00 PM
Evan, I think that Table in post 181 is about as good as you are going to get.
That is from an old book, the SKF book is too new and mimics the web site.
On Thursday this week I have to go visit a guy who's job was bearings, like everything to do with bearings. He also collects old bearing books as a hobby, in fact I have given him all mine with the exception of a few modernish design books.
Old bearings don't interest me as they are unobtainable.

Just out of interest I'll see if he has some info, if he has I'll photocopy it and scan it when I get home. Chances are that he will have.

Are there any more numbers / letter on it at all ?

.

Evan
01-04-2009, 08:16 PM
I can't look at the bearing as it is now installed in the housing but I found these markings in a photo I took. It appears to be a C2 clearance which on the new bearings is min 2 microns and max 18 microns. That would explain the numbers I got.

http://metalshopborealis.ca/pics5/bearing4.jpg

DICKEYBIRD
01-04-2009, 08:46 PM
Hey John, sir,

When you talk to your bearing expert, see if you can gather some info on how these complex bearings are built. I'm guessing the various parts are measured and sorted into containers of specific sizes then assembled in combinations to reach a specific set of tolerances.

The other thing that baffles me is how they are physically assembled in such a way that they can be assembled yet stay together once finished. Are they pressed together? Seems like the line between a proper press together fit and a pile of useless, damaged parts must be pretty fine.

Bearing designing and manufacturing has to be one of the most precise industries in the world. I wish I could go on an in-depth factory tour some time. We take bearings for granted and bitch about the prices but man, look how far we've come in a relatively short time!

dp
01-04-2009, 08:54 PM
Here's a youtube video on ball bearing construction:
http://www.youtube.com/watch?v=eGyoMuE4gDQ

DICKEYBIRD
01-04-2009, 09:14 PM
Awesome video Dennis, thanks!:)

J Tiers
01-04-2009, 09:19 PM
They kinda glossed over it, but for different classes of bearing, they would select balls and races that met the specs for the class, and assemble them.

"Generic bearings" of the lowest class get whatever meets basic spec.

darryl
01-04-2009, 09:27 PM
Evan suggested a while back that the preload would increase as the bearing was pressed onto the spindle. This would increase further if the outer race was press fitted into a rigid housing. My own feeling is that a bearing of that size is not going to suffer from becoming too tight unless the fits were too tight- something that a person of intelligence would avoid. I think that for almost every application on that lathe, both sets of balls are going to be supporting the spindle with a reasonable amount of load sharing- not necessarily equal, but not greatly unequal. The only thing that I see as a concern is if the spindle heats quite much- then the preload is going to increase, and the spindle length will grow, both having possible consequences. It is most likely however that the normal operating rpm will be low enough for these things to not be factors.

I'm not trying to rev up an agitated stallion here- I brought this up again because I have just gone through this press fit/pre load thing myself with some very small bearings. These are 3mm ID and 6mm OD, and are a light interference fit on a slot car axle and about a half thou press fit into a pvc bearing carrier framework. The first press fit had the bearing squeezed too tightly, the second try had the fit too loose and the pvc parts were scrapped. Taking almost nothing off the diameter of the D-bit I used to size the holes had the fit pretty good- of course being in the new framework. Checking the OD of the bearings, I could see a slight deviation from bearing to bearing, but less than a half thou or so, but that would be enough to make some too tight and leave some too loose. The pvc is obviously strong enough to compress the outer race, so I would suspect that mounting these bearings in a metal would require even closer fitting, and custom fitting per bearing as well.

Sorry to hijack a bit, but this direct experience of mine could be informative to some.

Evan
01-04-2009, 10:15 PM
The amount of interference of the inner race on the shaft most definitely affects the preload. The clearance numbers are given for the uninstalled condition. With mine I made it an interference fit of several tenths and then chilled the shaft with snow. I warmed the bearing to around 150 according to my IR thermometer and tested the fit. It didn't quite slide on so I gave it a firm push. On it wnet and immediately decided it wasn't coming off. That's why it ended up being there while I was machining the shaft. I don't know how much difference the fit makes but it must make some difference. Nothing is rigid.

J Tiers
01-04-2009, 10:20 PM
The fit is probably figured into the use, and a spec for that would have existed most likely...... because the fit on the shaft would expand the inner race and exert pressure on the balls and outer race, altering the load.

The earlier concerns about possible clearance or minimal preload are obviously affected by expansion due to fit.

Forrest has expounded on that before, IIRC. Might not have been here..... over at PM perhaps?

John Stevenson
01-05-2009, 05:35 AM
One note about fitting large bearings, going slightly sideways on the topic but I think it's interesting.

I read an article some while ago where Brush Electrical at Loughborough in the UK we working on some massive motors for rail traction, usual design rotor / armature supported on two bearings.

Bearings were a press fit in the housings and on the shaft. They found that if they press fitted the bearing on the shaft and loctited the bearing into a 3 thou oversize housing on test they were getting about 25 more horsepower from the same motors.

It was put down to the rotor finding it's best position.

J Tiers
01-05-2009, 09:25 AM
Interesting.

I wonder how MUCH their original press fit was. And what the clearances were before the press vs after. it's not clear as to whether the press-fit made interference, or if it cocked the bearings.

But 25 HP lost, if it went into friction, would be about 18 kW of heat to dispose of somehow. You would think they would have noticed that. And if it went into the bearings 18 kW would have cooked even a large bearing, it is equal to about 10 of the largest size electric space heaters.

Presumably it was not friction, but it is difficult to see what 0.075 mm would do in terms of rotor centering and any resulting power changes.....

Did they have any reasons why such a small change of "best position" would make a significant HP change?

Evan
01-05-2009, 10:14 AM
Iron and quite a few other elements exhibit an effect in magnetic fields called magnetostriction. Any piece of iron in a magnetic field changes shape. This is proportional to the size of the object and the strength of the field. It can be a significant amount and is what makes a transformer hum. It may have been causing some sort of bearing problems in the afore mentioned motors. I assume there were bearing problems or they wouldn't be replacing them.

John Stevenson
01-05-2009, 10:23 AM
No these were brand new motors, Brush is the manufacturer.
I also forgot to say that when assembled the rotor was turned with a slave motor to line up and allow the bearing to 'set' in the correct position.

Evan
01-05-2009, 11:22 AM
Brush is the manufacturer.


Do they also make brushless motors?

aboard_epsilon
01-05-2009, 11:52 AM
http://www.brushtraction.com/frame1.htm

lazlo
01-05-2009, 01:55 PM
Bearings were a press fit in the housings and on the shaft. They found that if they press fitted the bearing on the shaft and loctited the bearing into a 3 thou oversize housing on test they were getting about 25 more horsepower from the same motors.

when assembled the rotor was turned with a slave motor to line up and allow the bearing to 'set' in the correct position.

John, you've posted this before, and it's intriguing. That's basically saying that Loctite centers the bearing pocket better than you can with careful boring.

Do you have a link to the article?

Has anyone tried both methods and can comment on the conventional method versus the Loctite method?

dan s
01-05-2009, 02:01 PM
That's basically saying that Loctite centers the bearing pocket better than you can with careful boring.

It would be interesting to see some greater detail on this subject. my guess is that the loctite allows the bearing to expand more when it reaches operating temp.

lazlo
01-05-2009, 02:12 PM
The last time John posted that tidbit (about a year ago) I tried Googling it, but couldn't find any mention of Loctite and improved runout, alignment, ...

I'll try searching the Brush web site...

Evan
01-05-2009, 03:36 PM
If they did make brushless motors what brand name would they use?

small.planes
01-05-2009, 04:02 PM
Hmm that would be Brush Electrical Machines, (BEM) They only make SERIOUS Motors. Better known for their Generating sets I suspect.
The MAX motors are a DAX 2 pole set run backwards (ie a motor not a generator) IIRC in the region of a few MW (yep not a typo MegaWatts :eek: )
I suspect the Loctite trick is a goodun because of the problems of aligning the end caps on a machine thats a few meters long and when the end caps weigh several tonnes.

I used to work there...

Dave

noah katz
01-05-2009, 04:22 PM
"They found that if they press fitted the bearing on the shaft and loctited the bearing into a 3 thou oversize housing on test they were getting about 25 more horsepower from the same motors.

It was put down to the rotor finding it's best position."

It has hard to imagine dissipating 25 HP as heat (but how big are these these), but my guess would be that the Loctite is much more compliant allows deforming much less of the balls and races where the press fit may have resulted in having to deform all of them all the time.

Evan
01-05-2009, 04:28 PM
I have been told that my sense of humor is too dry. Apparently that must be true.

aboard_epsilon
01-05-2009, 04:29 PM
I have been told that my sense of humor is too dry. Apparently that must be true.

ok i was going to put "broom" ...but i thought ...noooo

all the best.markj

motorworks
01-05-2009, 05:44 PM
Read a lot of bull and brilliance so far...

Here is a link to some good info:

http://www.bearings.machinedesign.com/

John Stevenson
01-05-2009, 05:51 PM
John, you've posted this before, and it's intriguing. That's basically saying that Loctite centers the bearing pocket better than you can with careful boring.

Do you have a link to the article?

Has anyone tried both methods and can comment on the conventional method versus the Loctite method?

No link, it must have been about 10 to 12 years ago, I might be mistaken with the 25 HP bit but I remember it was a lot.
It definitely was Brush at Loughborough.
Perhaps a trawl round the Loctite site might help, after all this is a feather more in their cap.

Evan,
One of my customers has had a staffing problem and he's asked me to take one of the trucks down south in the morning, I'll call in and see the bearing guy tomorrow instead of Thursday.
Hopefully may get some 20 year old specs to match the 20 year old bearing.

.

lazlo
01-05-2009, 06:25 PM
Hmm that would be Brush Electrical Machines, (BEM) They only make SERIOUS Motors.

Good Lord -- they have 300 MWatt turbogenerators! That's 470,000 Horsepower :) Must have been a big tube of Loctite! :D

Really cool brochure on the DAX 2 generators that Dave mentions:

http://www.brush.eu/10461.file.dld

I plowed their website, but nary a mention of Loctite...

dan s
01-05-2009, 07:39 PM
I found this: :D

http://www.henkelna.com/us/content_data/ACH232_Loctite_RC_680_Retaining_Compound_Extends_H ousing_and_Bearing_Life.pdf

J Tiers
01-05-2009, 09:46 PM
I went to a bearing company a couple years ago, LOOKING for the loctite bearing retaining compound.

They were a loctite dealer, AND they did bearings, but would you believe it, they had NO idea what i was talking about. it wasn't even in their catalog....... Did I mention their main business IS bearings?

Apparently it is a very well-kept secret. or it is ONLY available in 50 gal drums to OEMs. No idea which,.... maybe both.

J Tiers
01-05-2009, 09:51 PM
Read a lot of bull and brilliance so far...

Here is a link to some good info:

http://www.bearings.machinedesign.com/

There sure is some good stuff there.....

If certain people read it, they might start agreeing about some factors I mentioned a while back ;)

wierdscience
01-05-2009, 10:39 PM
I can't look at the bearing as it is now installed in the housing but I found these markings in a photo I took. It appears to be a C2 clearance which on the new bearings is min 2 microns and max 18 microns. That would explain the numbers I got.

http://metalshopborealis.ca/pics5/bearing4.jpg

That number looked vaguely familiar so I went looking at Consolidated Bearing.Sure enough it's listed sort of.

http://www.consbrgs.com/interchange.taf?letter=5

On that interchange page look for number 5310 E 2RS.That shows the crossection of a Double row,angular contact ball bearing,Max type with a filling slot.It's very similar to the original crossection you posted.However this bearing isn't availible with the NR designation(snapring OD) as it must have a filling slot to be assembled.

5310-E-2RS

http://img.photobucket.com/albums/0903/wierdscience/cbcpic_606.gif

Now if you look at a 5310-2RSNR what you have is a conrad type(no filling slot)double row angular contact bearing with two rubber seals and the NR designation( snapring on the od)

5310-2RSNR

http://img.photobucket.com/albums/0903/wierdscience/z174csr.gif

If what I am seeing is correct the bearing you are using shows a snapring on the OD,which the Max type would not have.If there are also no filling slots then the bearing is definately a 5310-2RSNR.

Edit: there is one other possibility.If the width were special,wider than 44.4mm then it would be possible to be Max type with a filling slot,but since it's sheilded and we don't see any half moon slots in either race I tend to doubt it is.Consolidated also shows a 5310-CZZG,but it is the same crossection as the 5310-2RSNR.

lazlo
01-05-2009, 10:59 PM
I went to a bearing company a couple years ago, LOOKING for the loctite bearing retaining compound.

Apparently it is a very well-kept secret. or it is ONLY available in 50 gal drums to OEMs. No idea which,.... maybe both.

That's Loctite 680 Bearing Retaining Compound. Just about any machinist supply, including MSC and Enco, carry it.

I think I paid $7 for a .34 fluid ounce bottle at Enco.

Evan
01-05-2009, 11:00 PM
Yep, that's about what I was able to find too. No filling slots and I do know what they look like. I have "rebuilt" some bearings like this in the past.

It really doesn't matter. I am going to use it.

J Tiers
01-05-2009, 11:20 PM
That's Loctite 680 Bearing Retaining Compound. Just about any machinist supply, including MSC and Enco, carry it.

I think I paid $7 for a .34 fluid ounce bottle at Enco.

I wonder why the bearing folks didn't know about it?

I didn't have the 680 number, so I was asking more generically. Good thing I was really there to pick up some stuff, or I would have wasted the trip.

wierdscience
01-05-2009, 11:21 PM
Yep, that's about what I was able to find too. No filling slots and I do know what they look like. I have "rebuilt" some bearings like this in the past.

It really doesn't matter. I am going to use it.

If it doesn't work to satisfaction there is a fix.

Chuck the bearing by the ID and with a(SEVERAL DOZEN) thin cutoff wheels in a Dremel tool split the inner ring,presto,pre-loadable:D:D

lazlo
01-05-2009, 11:31 PM
I wonder why the bearing folks didn't know about it?

I didn't have the 680 number, so I was asking more generically.

I'm looking at the bottle right now, and doesn't say anything about bearings on it :) It says "Loctite 680 Retaining Compound Slip Fit".

I used the 680 to repair the rack and pinion on my Bridgeport slotting head: when I turned down the torn section of the old pinion gear, it was a loose slip fit on the replacement Martin gear I bought. I turned a little centering spacer, applied the Loctite 680 per the instructions, and the pinned it with a scotch key. The Loctite 680 datasheet says it will fill up to a 15 thou gap. I think there's a 682 or 690 variant thats thicker that will fill even bigger gaps.

In any event, I don't think the new pinion is going anywhere :)

J Tiers
01-06-2009, 12:27 AM
On that interchange page look for number 5310 E 2RS.That shows the crossection of a Double row,angular contact ball bearing,Max type with a filling slot.It's very similar to the original crossection you posted.However this bearing isn't availible with the NR designation(snapring OD) as it must have a filling slot to be assembled.

Now if you look at a 5310-2RSNR what you have is a conrad type(no filling slot)double row angular contact bearing with two rubber seals and the NR designation( snapring on the od)

If what I am seeing is correct the bearing you are using shows a snapring on the OD,which the Max type would not have.If there are also no filling slots then the bearing is definately a 5310-2RSNR.

Edit: there is one other possibility.If the width were special,wider than 44.4mm then it would be possible to be Max type with a filling slot,but since it's sheilded and we don't see any half moon slots in either race I tend to doubt it is.Consolidated also shows a 5310-CZZG,but it is the same crossection as the 5310-2RSNR.

I'm not totally sure I followed the logic, but I am looking at a 5207 bearing.... It is definitely a double-row, definitely an angular contact, it has filling slots, one shield, and an exterior snap-ring.

it is 27mm wide. Perhaps not all manufacturers have the same restrictions. Or the issue is specific to that size.

wierdscience
01-06-2009, 01:23 AM
I'm not totally sure I followed the logic, but I am looking at a 5207 bearing.... It is definitely a double-row, definitely an angular contact, it has filling slots, one shield, and an exterior snap-ring.

it is 27mm wide. Perhaps not all manufacturers have the same restrictions. Or the issue is specific to that size.

Upon further research it is possible to get a 5200 or 5300 series bearing in either conrad or max type.

The only catch is the max type are capable of full thrust in one direction and light thrust loads in the other,probably due to the filling slot.

Looking through the SKF website it seems though that the E type are more difficult to find in the 5200 series.----

SKF Ball Bearings Roller Bearings
E-type (maximum capacity)

SKF E-type double-row ball bearings have filling notches on one side to permit assembling the maximum number of balls into
the bearing. Similar to the conrad-type, the contact angles in the max-type design converge outside of the bearing. E-type bearings
are available with seals, shields or snap rings, or a combination of these components. The bearings have the capacity to handle
heavy radial loads. They also have thrust capacity in one direction, with the ability to accommodate light thrust load in the reversing
direction.

Max-type bearings are available in 5200 and 5300 series in a wide range of sizes. A pressed steel snap-on cage is standard for this
bearing type.

Kd0afk
07-04-2013, 12:59 PM
Looks awesome so far.
I am surprised you did not make a larger chuck mount, and go with a 5C spindle.
I know your SB uses 1 1/2-8 and that is why you stuck with it, but 5C is so sweet. You could make a threaded adapter for your SB to go from 1 1/2-8 to 2 1/4-8. or whatever it is that SB also uses. Then you could still switch chucks. Perhaps 5C is not your thing, I get that. But you also want 16" of swing? with a small 1 1/2" chuck mount? I just wanted to spark your ideas before you get to far into it. FWIW, an A-type spindle nose is easier to make than a camlock, and even more rigid. I never minded the bolts. Just thinking out loud. Sweet bearings, by the way.
--Doozer
I agree. I've been trying to decide on a collet system and I wish my SB9 was big enough to use 5c colletts like the 3c ones. 5c has more capacity and the 3c collets are almost 4 times as expensive. Great build by the way.

Evan
07-04-2013, 06:10 PM
The lathe does what I built it to do which is to cut large diameter parts. There was far too much concern in this thread about bearings, it really didn't matter much. I use the lathe to do things like cutting flat the edge of a cut off propane tank in order to turn it into a spray tank for driveway sealant. I don't need it often but when I do need to cut up to 16 inches it beats the heck out of my 9" South Bend.

studentjim
07-04-2013, 08:14 PM
It couldn't have been said better. Carry on Evan.
Evan,

that is a top job.

Congratulations on taking it on, thinking it out, making best use of what you have as well as fending off the "barbarians", "nay-sayers" and "Doubting Thomas-es".

As usual when "bearings" comes up, there is more "charting" and "consulting" and quoting of "learned works" than there would be at an astrologist's gab-fest.

All the "ifs" reminds me of the old saw that "IF your auntie had balls she'd be your uncle", and there's more "buts" than there are in ten Billy-goats.

At least you are having a go and getting your hands dirty instead of sitting on your freckle prognosticating and pontificating. Some won't need a bridge to get over Williams Lake - they can walk over it!!

Or to (sort of) quote the Bard and the Prophet - f*ck 'em!!

I think that Lane - as usual - has injected a lot of common sense as well as confidence in your ability and the ultimate outcome.

I agree with Lane.

I rather think that your project and credibility will come out in better shape that the credibility and egos of some others.

If YOUR new lathe does what YOU want it to do, then by any measure it is a total success - irrespective of the opinion of anyone else.

Your track record is first class thus far and I can't see you blotting your copy-book on this project or anytime soon.

I am looking forward to seeing it in use.

Toolguy
07-04-2013, 08:24 PM
Are there any pictures of the finished machine? I didn't see any but could have overlooked something.

Evan
07-05-2013, 12:56 AM
I have a few a bit further along than this one but I don't know where they are right now.

http://ixian.ca/pics10/ixlathe.jpg

Toolguy
07-05-2013, 01:04 AM
Thanks Evan. That's a very nice looking lathe. It is definitely one of a kind.:)

dp
07-05-2013, 03:46 AM
Thanks Evan. That's a very nice looking lathe. It is definitely one of a kind.:)

I've seen it in person - it's awesome. Besides having a number of desirable characteristics, the wood is beautiful.

Paul Alciatore
07-05-2013, 01:54 PM
It looks really nice and probably excellent for your stated purpose.

I am curious, did you make a tailstock for it?

dian
07-05-2013, 02:20 PM
so it is really wood? why? what exactly was used for the "ways"?

and what kind of wood, what was the percentage of humidity and haw much did it shrink/deform over time?

Evan
07-05-2013, 08:28 PM
I really don't want to discuss it any more. It works the way I need it but the entire discussion around it in the past put me off from talking about it any more.

Black_Moons
07-05-2013, 09:05 PM
Very nice lathe evan. Love the wood inlays. the chain drive system looks nice too. Very stylish overall.

iMisspell
07-06-2013, 03:32 AM
Not sure what i like more - the lathe or the picture... thats pretty cool how the lathe is in color but everything else is Black-n-White and slightly blurry.

Thumbs-up to both.

_

ulav8r
07-06-2013, 09:17 PM
Dian,

If you would read the whole thread, your question would be answered and you would understand why Evan doesn't want to discuss it further.