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View Full Version : oddball angular contact bearing for a grinding spindle....any ingenious ideas?



Mcgyver
07-24-2012, 04:05 PM
I've a Wolf Electric internal grinding spindle for a tool post grinder with shot bearings. Wolf was absorbed eons ago and is a dead end. The beaing maker, R&M, also isn't to be found or at least i haven't found them.

They're an odd size, angular contacts 35 od, 14 id and 9mm thick.

Any ideas on a source or creative ways to machine my way out of this mess?

thanks

EDIT....turns out R&M is RANSOME & MARLES ....found a site. We'll see if they have them and if I can afford them.

lazlo
07-24-2012, 05:07 PM
They're an odd size, angular contacts 35 od, 14 id and 9mm thick.

It's pretty close to a 6202: 35 x 15 x 11. You'd have to modify the pocket and sleeve the shaft...

rythmnbls
07-24-2012, 05:17 PM
A 6002 is a bit closer at 15x32x9

Just need to sleeve the shaft

Steve.

John Stevenson
07-24-2012, 05:23 PM
Closest is going to be an E15 angular contact magneto bearing.
You will still have to sleeve the shaft but they are 35 x 15 x 8 and good for 20K with grease, 25K with oil.

lazlo
07-24-2012, 05:40 PM
A 6002 is a bit closer at 15x32x9


6002 is a radial bearing, not an angular contact bearing.

John's magneto bearing is close, but it's not a precision bearing. Works for a Quorn, YMMV :)
Are magneto bearings even available on this side of the pond anymore?

John Stevenson
07-24-2012, 06:04 PM
6002 is a radial bearing, not an angular contact bearing.

John's magneto bearing is close, but it's not a precision bearing.

Bollocks of course it's precision to run at 20 K, bet you can't make one better ;)

TGTool
07-24-2012, 06:10 PM
John's magneto bearing is close, but it's not a precision bearing. Works for a Quorn, YMMV :)
Are magneto bearings even available on this side of the pond anymore?

At least three options listed with Motion Industries - Federal Mogul, Consolidated Bearings and ZVL-ZKL Bearings for $42, $31, and price-on-request respectively.

lazlo
07-24-2012, 06:27 PM
Bollocks of course it's precision to run at 20 K

I'll see your bollocks and raise you a bullsh!t :) A common skate bearing is rated to 33,000:

http://www.smbbearings.com/Popular_Metric_Bearings.htm

Professor Chaddock is very clear in the Quorn (tool and cutter grinder) book that he chose magneto bearings because he couldn't afford real angular contact bearings. ;)

lazlo
07-24-2012, 06:28 PM
At least three options listed with Motion Industries - Federal Mogul, Consolidated Bearings and ZVL-ZKL Bearings for $42, $31, and price-on-request respectively.

That's more expensive than a bonafide angular contact bearing.

John Stevenson
07-24-2012, 06:34 PM
I'll see your bollocks and raise you a bullsh!t :) A common skate bearing is rated to 33,000:

http://www.smbbearings.com/Popular_Metric_Bearings.htm

Professor Chaddock is very clear in the Quorn (tool and cutter grinder) book that he chose magneto bearings because he couldn't afford real angular contact bearings. ;)

I'll see your bullshėt and raise you a cowpat.


So you are telling me that Professor Chaddock, [ 3 Hail Marys, two Mituoyo's a Starrett and a Moore and Wright ] OK'd it to be used on THE QUORN [ 37 Hail Marys, 15 Mituoyo's, 17 Starrett's and 10 Moore and Wright's ] but they are not suitable for a lowly Black and Decker ? :confused:

lazlo
07-24-2012, 06:39 PM
So you are telling me that Professor Chaddock OK'd it to be used on THE QUORN but they are not suitable for a lowly Black and Decker? :confused:

I must have mis-read Mike's OP -- I thought these were bearings for a precision internal grinding fixture. But sure, good point for a Black & Decker :D

rythmnbls
07-24-2012, 08:00 PM
6002 is a radial bearing, not an angular contact bearing.


Correct, but generally, if you subsititue a 7 for the leading 6, you get a standard angular contact equivalent, ie a 7002, vxb bearings has them for about $7 each, or up to $197 if you want an abec 7.

Regards.


Steve.

lazlo
07-24-2012, 08:05 PM
you get a standard angular contact equivalent, ie a 7002

Good point -- those are the thin cross section angulars: 7002 = 32 x 15 x 9

TGTool
07-24-2012, 08:51 PM
Professor Chaddock is very clear in the Quorn (tool and cutter grinder) book that he chose magneto bearings because he couldn't afford real angular contact bearings. ;)

Robert, I didn't remember him being that specific in discussing his bearing choices and took a quick look through the book without finding that. Do you remember where you saw it?

Rich Carlstedt
07-24-2012, 11:15 PM
Just get a Barden E 14
35 x 14 x 8

Rich

Mcgyver
07-25-2012, 08:44 AM
I owe you guys an apology - they're 8mm not 9mm thick...although it was the diameters that made the fit tricky. Using ones that were close occurred to me, but 1/2mm thick sleeves that don't themselves create a bunch of new problems seemed a challenge.

Rich, I looked at a Barden catalogue - are the E14in a specialty catalogue - where did you find those? Barden; is this a part mere mortals can afford :) There stuff can get up there in a hurry.

I did find a source for these bearings in the UK, just try to ascertain whether they're old stock or not. Also had a helpful PM about a Canadian supplier. Looks like 35x14 isn't the impossibility I thought it was. thanks for all the help

So there's E14, M14, A14....all seem to be 35x14x8...any idea on what the letter prefix is?

lazlo
07-25-2012, 09:06 AM
So there's E14, M14, A14....all seem to be 35x14x8...any idea on what the letter prefix is?

The E series (E14) and the A series are magneto bearings. They're a common deep-groove bearing with one shoulder on the outer ring removed.

The runout will be typical for an ungraded bearing. That's why Prof Chaddock directs you to install the magneto bearings, machine the taper in-situ, and then never take it apart, even for maintenance, since you won't be able to get the parts back together in the same orientation.

wierdscience
07-25-2012, 09:09 AM
So there's E14, M14, A14....all seem to be 35x14x8...any idea on what the letter prefix is?

E= special runout .00005" in the case of the E-14


http://www.ahrinternational.com/BARDEN_nomenclature.shtml

Mcgyver
07-25-2012, 09:18 AM
ok thanks....so the M14's I've found (and represented as angular contact bearings) are a different animal than the E's or A's. They're @ 19 pounds each....pricey but not stupidly so.

lazlo
07-25-2012, 09:20 AM
E= special runout .00005" in the case of the E-14
http://www.ahrinternational.com/BARDEN_nomenclature.shtml

That doesn't surprise me -- I don't think Barden makes any non-precision bearings anymore.

Mike: A-XX and E-XX is the standard nomenclature for a magneto bearing. So if you buy an E-14 from anyone else besides Barden, it's probably not going to be a precision bearing:

http://simplybearings.co.uk/shop/product_info.php?products_id=42612

That link actually has a great picture showing the construction of a magneto bearing: it's literally a common radial bearing one one race ground off, so the cage just sits in there. That's why they're usually used in pairs, with the inner races preloaded against each other:

http://i164.photobucket.com/albums/u15/rtgeorge_album/mag.jpg

Mcgyver
07-25-2012, 09:53 AM
That link actually has a great picture showing the construction of a magneto bearing: it's literally a common radial bearing one one race ground off, so the cage just sits in there. That's why they're usually used in pairs, with the inner races preloaded against each other:



The person at RANSOME & MARLES calls the M14 an angular contact bearing....but looking at the above image I'm not sure I know how to differentiate between magneto and angular contact just on visual inspection. I've asked R&M to confirm they're angular contacts will put up some detailed pics later on detailing the bearings that came out of it
thanks

lazlo
07-25-2012, 10:05 AM
The person at RANSOME & MARLES calls the M14 an angular contact bearing....

That's why I was asking if anyone still made magneto bearings. Like the modified radial bearings that Bridgeport used to ship for spindle bearings, they're from an era when angular contact bearings were rare and expensive.

TGTool
07-25-2012, 12:34 PM
My understanding is that what differentiates magneto bearings is that the inner and outer races are separable. Apparently that was important for some installations. If you look at one in the flesh (in a manner of speaking) you can see the features that provide the high and low sides of the races and thus the contact angle. I couldn't tell what the angle was, but could see that there was one.

Mcgyver
07-25-2012, 12:59 PM
RANSOME & MARLES initial communication called the M14 an angular contact bearing......when I asked to confirm that part was angular contact they sent me the R&M original spec.....wait for it.......magneto bearings! M14 isn't angular contact, they're magneto bearings...John take a bow :D

Yes the races easily fall apart, but it's been so long since i had angular contacts in my hands I couldn't remember whether they did not

calling around for prices....will report back on the Barden bearings cost just for kicks.

an informative thread, thanks for all the input

willmac
07-25-2012, 02:01 PM
Angular contact bearings will also separate easily, at least the 7202 I am currently working with does and others that I have seen are the same.

rythmnbls
07-25-2012, 02:02 PM
Interesting,


Like the modified radial bearings that Bridgeport used to ship for spindle bearings

Sounds similar to what we do to convert a standard radial bearing for use in micro gas turbines, the bearing is dismantled, one side of the inner race is ground off and the balls are replaced with Silicon Nitride balls. The cage is discarded and enough balls are used to make the bearing a full compliment type.

Regards.

Steve.

JoeLee
07-25-2012, 09:38 PM
I would look up Fafnir and see what they have. They may have a direct replacment. I had a PDF doc. on all the precision spindle bearing but I can find it, if I do I'' post it.

JL.........................

Rich Carlstedt
07-26-2012, 01:27 AM
Barden E-14
Fafnir 14 and 14-1
FAG E-15
Federal FB14
Norma FAG E-14 and SP15
SKF E14
Torrington T14

Take your pick, all are magneto 14-35-8 in size
Many are no longer available
All magneto bearings are open type bearings and matched in pairs.

Rich

darryl
07-26-2012, 03:48 AM
I have no wish to throw confusion on things, but I had a thought or two- these 'magneto' bearings, or angular contact bearings- grinding away one side of the race doesn't turn a deep groove bearing into an angular contact bearing. If that was the case, then any deep groove bearing would be an angular contact bearing simply by virtue of applying pre-load. If the assembly method can stand using bearings which don't come apart, then you can base your choice of bearing on other things- size obviously, seals and or shields, ABEC rating, etc.

I'm not doubting that a magneto bearing might be the best choice here- it probably is- but I would like to see that it has 'higher' walls in order to give it a higher axial load capability than a comparable deep groove bearing, and thus earn the descriptor 'angular contact bearing'.

lakeside53
07-26-2012, 10:43 AM
Fanir/Timken also makes (made) magneto bearings in sealed form. I put a pair in the top pulley of a bp head - worked perfectly!

Mcgyver
07-26-2012, 11:24 AM
Rich, I can't find Barden E 14's, neither could consolidated bearings although there is an FAG E14 (who owns Barden)...you mentioned them a couple of times; do you know they're out there and I'm just not looking in the right places?

Think i will go with SKF, easy to find locally.

Darryl, Perhaps given how light the loads are, and the preload is a light spring, deep grooved would work. I can't fault the logic of that being the functional equivalent of the magneto bearings. There is no need for the bearings to come apart for this assembly. I agree it would be nice to have choice on the other characteristics, but the challenge seems to be the size is unique to the magneto bearings; no regular angular contact series gives me that 14mm bore. I'd guess what I'd gained in going with a higher class angular contact bearing I'd lose trying manufacture ridiculously thin sleeves etc. Besides, its not clear there'd be a performance advantage assuming the rest of the tool was in keeping with the quality/precision of the bearings used....and it is for use with a tool post grinder :D

Rich Carlstedt
07-26-2012, 12:24 PM
No, I can't tell you if any are out there, just passing on my reference info.

In that past , having some shop equipment dating back to the 1800's, replacement parts are not an everyday occurance.
I spent almost 2 years finding a special spindle bearing at one time, and got it on eBay.
My 1930's B&S #2 Surface grinder had ball bearings when I got it back in the 70's and I never was able to match the BB's in the head, and I don't even know if they were original equipment ? I didn't have a manual and what I did see on others was different.
I scrapped it out after several years of use.

You may want to consider a 17 x 35 x 10 substitute instead of the 15 mm bore
That would be a Barden 103 H bearing (spindle - 15 deg angular contact)

Barden only makes precision bearings , so i have a leaning towards them

Hope this helps
Rich

lalatheman
11-08-2012, 07:10 PM
Sounds similar to what we do to convert a standard radial bearing for use in micro gas turbines, the bearing is dismantled, one side of the inner race is ground off and the balls are replaced with Silicon Nitride balls. The cage is discarded and enough balls are used to make the bearing a full compliment type.


Wow now thats interesting, what kind of rpm's do these turbines hit ?
How much free space is left in a ring of bearings when it is classed as " full complement"
According to what i remenber from SKF or Barden online info one of the advantages of an AC bearing over deep grove is that more balls can be inserted. Also that a principal advantage of ceramic balls over steel is weight therefore less centrifical force. I dont know if Silicon Nitride balls are considered "ceramic" Do you guys do this conversion principally to save cost?
I have several times considered using parts esp balls which are very inexpensive in bulk and "making" bearings also. Isnt there some easy ,or as least low tech and effective way to sort and size balls down real small to have a more closely matched set?

I really enjoyed hearing that you were doing this operation.

Dave

darryl
11-08-2012, 10:32 PM
I find it amazing that the production of steel balls to a high degree of sizing accuracy and roundness is possible at the relatively low price you can buy them for in bulk. I know the carbide balls are a lot more money, but that's understandable.

Making your own races, sure why not. If you are willing to take the time to make and use some of your own tooling, use bearing steel, and use proper heat treating and machining procedures, it can be done. I've done it. I'm not saying my bearings even deserved an abec rating, or would have gone trillions of rotations without problems, but they worked. I'm thinking that the final machining should be an averaging process which should even out any out-of-roundness in the grooves and lessen the requirement for your lathe spindle bearings to be perfect. It would be interesting to know if there's some 'special' procedures in general manufacturing of bearings that enhance the smoothness and roundness of the races- I'm thinking that there would be some version of this that you could do in the home shop.

You might spend hours making one ball bearing race, but if that allowed you to get something in your hands as opposed to not being able to get it or afford it, then maybe it's workable.

rythmnbls
11-09-2012, 07:13 AM
Wow now thats interesting, what kind of rpm's do these turbines hit ?

Larger turbines top out at 100-120k, the smaller ones run as high as 200K.

I have a converted set of bearings in a larger turbine that I am building, during testing it has reached 50K rpm and the bearings seem fine so far. A few pics here (http://s87.photobucket.com/albums/k142/madluther/Turbine%202/).


Do you guys do this conversion principally to save cost?

Cost is a factor, the bearings have to be full compliment, the cages on a normal bearing will tend to fly apart under the centrifugal forces at play. The ceramic balls are lighter, have much higher compressive strength, handle high temps, they don't "onion peel" like a steel ball will when overstressed and are much freer running.


Isnt there some easy ,or as least low tech and effective way to sort and size balls down real small to have a more closely matched set?

You can buy them graded, normally I use G3 or G5 grade balls, G3 are spherical to .000003" and G5 to .000005".

You can find more info at bocabearings.com and vxb.com.

Regards,

Steve.

tdmidget
11-09-2012, 07:41 AM
Steve your engines are interesting. It appears that they are reaction engines ie; not turboshaft. The compressor wheel appears very similar to one from an APU. I used to work in a FAA repair shop where we rebuilt APUs and their parts. Is that what it is? Also why not plain bearings, the simplest and longest last lasting that there is? Alll the APUs that I remember had plain bearings.

rythmnbls
11-09-2012, 09:11 AM
The compressor wheel appears very similar to one from an APU

Its a TO4E-54 compressor wheel from a Garret turbocharger.


Also why not plain bearings

The primary reason is lubrication. Plain bearings in this application need a pressurized oil supply, which means an oil pump and usually a larger scavenge pump, plus oil coolers and filters, that adds a lot of weight and complexity, the current lube system uses a premix system similar to a 2 stroke engine. There is 3-5% of oil premixed into the fuel, this fuel mixed with some bleed air from the compressor is used to create a lube mist which is fed into the front bearing, travels down the shaft tunnel to the rear bearing and then exits behind the turbine wheel and is lost. Lube supply comes from the fuel pump via restrictor to limit the lube rate to one or two drops per second.


It appears that they are reaction engines ie; not turboshaft.

This one is a pure jet in its current form, I would like to add a free turbine stage at some point and see what kind of work it could do.

Regards,

Steve.

oldtiffie
11-09-2012, 06:56 PM
These high speed spindles whick look to be very good all have ceramic angular contact bearings - a possible bearing/solution?

http://www.arceurotrade.co.uk/Catalogue/High-Speed-Spindles-Motors-Inverters