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brian Rupnow
04-18-2014, 09:51 AM
I am considering buying a toolpost grinder from Little Machine shop. The site doesn't give a lot of information about them, and I have never used one before. It says that to use them you must remove the compound rest from your lathe. If you do that, how could you grind anything on a taper? It says that they will fit a C6 or a SC6 lathe, which means very little to me because I have a BusyBee B2227L lathe and I don't know anything about the numbers they refer to on the website. Does anyone out there own a grinder like this? How useful is it. How do you grind a taper with it. they offer a number of different grades of grinding wheels for it. What grades of grinding wheel would you recommend. Can it grind 1018-1020 mild steel, or only hardened steel. Are there any good book available about the care and feeding of tool[post grinders? Any help would be greatly appreciated.---Brian

http://littlemachineshop.com/products/product_view.php?ProductID=4671&category=

Glug
04-18-2014, 10:04 AM
Hmpf! Well... I opened this thread expecting an epic Brian Rupnow tool post grinder build! I was just hoping it would not be a miniature.

Euph0ny
04-18-2014, 10:23 AM
I know nothing about the lms offering, but if you have a copy of 'the amateur's lathe' by Sparey, there is a section on toolpost grinders, and plans for a grinder spindle.

studentjim
04-18-2014, 10:48 AM
I am considering buying a toolpost grinder from Little Machine shop. The site doesn't give a lot of information about them, and I have never used one before. It says that to use them you must remove the compound rest from your lathe. If you do that, how could you grind anything on a taper? It says that they will fit a C6 or a SC6 lathe, which means very little to me because I have a BusyBee B2227L lathe and I don't know anything about the numbers they refer to on the website. Does anyone out there own a grinder like this? How useful is it. How do you grind a taper with it. they offer a number of different grades of grinding wheels for it. What grades of grinding wheel would you recommend. Can it grind 1018-1020 mild steel, or only hardened steel. Are there any good book available about the care and feeding of tool[post grinders? Any help would be greatly appreciated.---Brian

http://littlemachineshop.com/products/product_view.php?ProductID=4671&category=

Brian, with the Little Machine Shop tool post grinder, you would have to make some sort of swivel base similar to that on a bench vise in order to grind on a taper. Also, the center height of the grinder may have to be modified to match your lathe spindle. With your capabilities, you would probably be better off making your own, that way you could incorporate a way to do internal grinding as well. Just my .02 cents. I use an early model Rotozip with a simple bracket that fits in my QCTP. It works very well on smaller diameter projects, but because of the small footprint of the tool, it is limited to the size of grinding wheels.

brian Rupnow
04-18-2014, 10:49 AM
I guess maybe the second part of my question should be, does anybody sell a toolpost grinder that mounts to (wait for it----The TOOL POST!!!) That would seem t me to have a lot more versatility. (My toolpost is an AXA quick change style.)

Dunc
04-18-2014, 11:07 AM
Review here http://www.mini-lathe.com/C6_lathe/C6/c6.htm states that the C6 is a 10 inch lathe like the B2227L.
Lots of ideas here: http://www.cnccookbook.com/CCLatheTPGrinder.htm (not complete plans)

Some plans:
http://www.dm.net/~lughaid/grinder.htm
http://www.homemodelenginemachinist....-version-6165/
Popular Science Aug 1941
Popular Mechanics Aug 1944

There is a "how to" article in Popular Mechanics Nov 1949

The Workshop Practice Series #27, Spindles, has construction drawings for some toolpost grinders.

Jaakko Fagerlund
04-18-2014, 11:07 AM
About the wheels, just get something 40 or 60 grit, it gives you a very good finish and doesn't clo so easily. I don't know of the LMS wheel quality, I would search for CGW or Norton wheels that are known good brands.

As for turning tapers, yeah that thing would have to be modified to fit your compound. Or modified so that you can bolt a length of cold rolled flat or something to it so you can grab it in your tool post holder. Or make a tool holder that directly bolts to that thing.

Or just make the spindle cartridge yourself, make a tool post holder for it and run it from a small motor with belt.

RichR
04-18-2014, 11:28 AM
Hi Brian
Can't help with your question, but I do have a funny story. In high school the teacher set me up to regrind some dead centers. He had laid
a strip of damp newspaper across the ways to protect them. Somewhere around the third center the paper had dried up and then caught
on fire. Man was he laughing, but, lesson learned. One more, I got out of shop a little late so the English teacher sent me back to him for
a note. He wrote:

Please excuse Richard for being late. He cut off both of his thumbs, but he's better now.
George
He was my favorite teacher.

Toolguy
04-18-2014, 11:32 AM
I have a Dumore Model 44 toolpost grinder that easily fit on the compound of my old 12 x 40 lathe and my new 14 x40 lathe. No mods needed. I'm pretty sure it's bigger than the LMS one.

dian
04-18-2014, 11:56 AM
i would thing about what kind of bearings the contraption has. you might as well use a file. (btw, i would never ever grind on one of my lathes.)

boslab
04-18-2014, 12:45 PM
A little air pencil grinder in a clamp on the toolpost should do what you want, saw a toolpost grinder on ebay, on closer examination it was bloody gigantic, you would need a 13 to 16 swing lathe to fit it, mines 12 so not big enough.
Mark

Joe_B
04-18-2014, 01:18 PM
I use a dremel pencil grinder on a flex shaft. I put the grinder part into a boring bar holder and use my quick change toolpost to hold it just like any other tool. Yeah it isn't a dumore but it only cost me $50!

George Bulliss
04-18-2014, 01:21 PM
I've seen the LMS grinder at shows and it looks decent enough for the price. However, when I first saw it I was surprised at how big it is. It looked fine for my 13" but I had a hard time envisioning it on anything smaller.

stanger53
04-18-2014, 02:05 PM
I have one of those LMS grinders on my Harbor Freight 7x10 lathe, which is identical to a lot of other makes and models in that respect.

I have never needed to grind at an angle, but, yeah, you would have to modify the base to do that.

I have used this grinder to machine down spools and shafts on a pretty regular basis for about twelve years now. Used the stone that came with the grinder (80 grit, I think) for quite a while, but have used their 240 grit stone the last eight years or so. Just dress it occasionally and it cuts pretty smooth.

Over the years I have only had to replace the drive belt three times, and that's it. It may not be as precision as a $500+ grinder, but it works well within mini-lathe limits and is durable

loose nut
04-18-2014, 03:16 PM
I have one too and it is the only thing I have bought from LMS that I was disappointed with.

It wouldn't grind a smooth surface, chatter all over. It may not have been the grinder itself but the wheel. One of the salesperson, that I talked after I bought it, admitted that some of them won't do it. You would have to have a balancing rig, bought or made to get them ready to grind. Grinding isn't as straight forward as turning or milling.

krutch
04-18-2014, 03:52 PM
Brian,
I have one of the LMS grinders and intend to mount it on a BXA sixe tool holder. I have not done this yet. The lathe I want to use it on is a 15" swing. The Grinder looks to be fairly well built tool (for foreign built stuff). How it will hold up to the use I intend remains to be seen. I do not intend to do more than finish work with it. No heavy grinding. For that type of work, the LMS grinder should be just fine.

Unfortunately, There is no way to easily mount the grinder directly to a holder and I have to modify the grinder to mount it on a *XA tool holder. This is mostly why I haven't done so yet. I looked at not modifying it, only the tool holder. Looks like I need to make a tool holder so I don't need to mod. the grinder itself. It may be possible to mount one of these TP Grinders on some machines without the mods. and possible to mount to your cross slide or compound. It just takes some imagination.

If I ever get pass the design stage, I shall post a thread on it.

I did buy a used Thematic TP grinder off the "bay" which has a tool post holder fitting and is another reason the LMS project took a back seat. That tool needs some TLC to use it and is also on a back burner.
Been fist fighting health issues right now.

stanger53
04-18-2014, 03:57 PM
Sorry to hear that, loose nut. I have had great success with mine.

I started with an 80 grit stone, run the part opposite the grinding wheel with only enough speed to smooth out the turning of the lathe. Later I changed to the 240 stone and have cut a hundred or more hardened steel spools with no problems. The finish comes out like a fine brushed aluminum - smooth to the touch, but you can feel the roughness with a fingernail. About ten seconds each with some 600 grit and then 1000 grit emery paper, and the surface is shiny reflective smooth and slides through the seal cleanly.

I did notice after several years that the surface was getting a couple of deeper grooves cut in it, and that more polishing was required to smooth the surface out. It finally dawned on me that I had never dressed the wheel and the surface was not as smooth and flat as it was originally. A light dressing of the stone a couple of years ago and it is still grinding smooth and even.

I never had any problem with chatter. I would think that replacing the wheel would be your fix for that.

After a while,

Mike Burch
04-18-2014, 05:08 PM
Brian, when I bought my little Sieg lathe from the factory years ago I also bought every possible accessory – including a toolpost grinder that looks identical to the one in your link. As it turns out, I've never needed to use it, so I can't comment on its accuracy.
Yes, it does bolt directly to the cross-slide, not the compound. To grind a taper, you'd have to turn the work between centres and offset the tailstock.

phil burman
04-18-2014, 06:48 PM
Google "pictures of tool post grinders"

Phil:)

J Tiers
04-19-2014, 12:24 AM
The LMS grinder looks to be as big as a house.....

I had a Dumore 14, and now have a Dumore 44, and they are right-sized for a 10" or so lathe. The LMS looks way bigger..... On a mini-lathe I can't really imagine it....

I can put the Dumore 14 or 44 on the regular compound of the Logan.... No need to remove anything. They mount to a post that fastens down like any toolpost... Easy-peasy.

Try to get something else.... Not only does it look huge, but it also looks cumbersome and bulky.

The mounting method is the absolute worst I have ever seen..... At 14+ lb wight it is really heavy.

The absolute size is not that much bigger than a Dumore 44 (much bigger than a Dumore 14), but a lot of the bulk is up front near the wheel. It would get in it own way a lot.

Here is a Dumore 44, mounted on a stand for tool grinding (minus the pulley guard). You can see that the mass of the thing is really with the motor, and it has no huge bulky casting up near the wheel and work.

The goggles are on top for scale. You can also see the simple post mount, that allows adjusting for height, which is important if you intend to grind tapers. The plate is acting as the top of the compound, the flat round part would sit on the compound but is on top of the plate here

http://img.photobucket.com/albums/0803/jstanley/machines/Grinder/dumore44_zpsf108520c.jpg (http://smg.photobucket.com/user/jstanley/media/machines/Grinder/dumore44_zpsf108520c.jpg.html)

plunger
04-19-2014, 03:17 AM
This post is not in the spirit of things. I am sure many homeshop machinests log on every day for their machining fix to be dissapointed by your lazy attitude. Where are the wonderfull CAD drawings that mezmorize us and give us guys incapable of doing drawings or inventing things something to copy.
Come on Brian .There are not enough guys like you around who make a site like this amazing,.I hope you are not slowly becoming a cheque book engineer

The Artful Bodger
04-19-2014, 06:55 AM
Here is my attempt at a tool post grinder..

https://farm3.staticflickr.com/2685/4041384299_4387600998.jpg

I made two spindles, a high speed and one not quite so high.

https://farm3.staticflickr.com/2528/4042130644_7172679b1d.jpg

It clamps on top of the compound and is only a single bolt to mount. The motor is from a router and required quite a step down for the external grinding wheel.

Unfortunately I could not reverse the router motor but I did try and gave up when smoke came out of it! Most grinding therefore is done with the spindle reversed.

The external wheel now has a safety guard.

brian Rupnow
04-19-2014, 09:39 AM
Plumber--don't preach to me about lazy attitude!! I may be a lot of things, but lazy is not one of them. I know I could probably design and build a toolpost mounted grinder. Same for my car, my refrigerator, and my sewing machine!! Its just that I have an aversion to designing and building an item that I can purchase off the shelf and start using immediately.---Brian

AlanHaisley
04-19-2014, 12:19 PM
Plumber--don't preach to me about lazy attitude!! I may be a lot of things, but lazy is not one of them. I know I could probably design and build a toolpost mounted grinder. Same for my car, my refrigerator, and my sewing machine!! Its just that I have an aversion to designing and building an item that I can purchase off the shelf and start using immediately.---Brian
Brian,
I am anxiously awaiting the sewing machine design. :)
Alan

J Tiers
04-19-2014, 12:22 PM
Artful

I like your TPG. It's a good size, and should be handy to use.

Might want a guard, though....

loose nut
04-19-2014, 12:59 PM
I never had any problem with chatter. I would think that replacing the wheel would be your fix for that.



Possibly but I have qualms about using a tool post grinder on my lathe now. Potential for damage, even with precautions, is to great.

It will be used for something else.

boslab
04-19-2014, 02:39 PM
Anyone fixed a TPG to a horizontal mill!, seems plausable?
Mark

loose nut
04-19-2014, 03:21 PM
It's been done but I can't say how well it worked. Mills aren't built like surface grinders.

The Artful Bodger
04-19-2014, 07:02 PM
Might want a guard, though....

Yes JT, it got a nice guard on the wheel when my $10 angle grinder came to the end of its 20 minute design life!

boslab
04-19-2014, 09:38 PM
It's been done but I can't say how well it worked. Mills aren't built like surface grinders.
Sorry i didnt explain, shove a chuck in the spindle and bolt the TPG to the table to tackle big work if you see what i mean, i hadent considered using it like a surface grinder, however, im sure i will have to try now!
First buy a grinder, hang on why not bolt my little bench grinder to the table, lets cook
Mark

dp
04-20-2014, 02:46 AM
Regarding "never grind on a lathe", I've studied this topic as a candidate for metal working lore and have learned that there are those who will and those who won't grind on a lathe. Those who will and have have never reported any problems in significant numbers, and those who won't have also never reported any problems. Of the two groups those who have ground on their lathes have created useful products and those who have not have not. You don't often find this kind of agreement in researching machine operations. My conclusion is, get your grinder and use it. Take common sense precautions to protect the lathe from the stone fragments, and have a good time with it.

I have, BTW, and am happy with the results.

brian Rupnow
04-20-2014, 09:12 AM
I've decided not to buy one. If I can't grind a taper with it by setting the grinder on an angle its use would be too limited. For emergency situations where nothing else will work, I do have a machined aluminum bracket that mounts to my toolpost and holds my pneumatic high speed grinder very securely.---Brian

J Tiers
04-20-2014, 06:57 PM
Regarding "never grind on a lathe", I've studied this topic as a candidate for metal working lore and have learned that there are those who will and those who won't grind on a lathe. Those who will and have have never reported any problems in significant numbers, and those who won't have also never reported any problems. Of the two groups those who have ground on their lathes have created useful products and those who have not have not. You don't often find this kind of agreement in researching machine operations. My conclusion is, get your grinder and use it. Take common sense precautions to protect the lathe from the stone fragments, and have a good time with it.

I have, BTW, and am happy with the results.

That's a bit sweeping, perhaps.... that those who don't use a grinder on the lathe never create anything useful?

Hmmmmmmm.....

The damage from grinding will be slow to show up, and will be in proportion to useage. No matter HOW careful you are, you will get grit where it doesn't belong, or where it can't be cleaned without a complete teardown, and that WILL have consequences.

Consequently you won't see much in terms of bad consequences.... kinda like some industrial toxins..... takes long enough to do damage that when you notice finally, you have nearly forgotten that you (or in this case, it) were ever exposed.

I try to avoid it... but I have done it.

boslab
04-20-2014, 08:44 PM
Get an old lathe, just grind on that, good excuse to buy another!
If you already have an old machine like me it doesn't matter about the grit anyway, i don't do super precise work, don't need to, nothing i make is that precise, so long as it works!
If i need accurate kit in the future ill buy a new lathe!, thats my excuse anyway
Mark

dian
04-21-2014, 04:35 AM
so why would you actually want to grind on a lathe? because work is hard? you can hardturn. to get a better finish? when you do it right, you get mirror finish when turning. and didnt someone just mention, he was polishing the ground surface? because you want more precision? where would that come from. grinders are built to precision levels 2 - 3 x higher than lathes.

dp
04-21-2014, 05:59 AM
You grind on the lathe when it is your only option for the job. As for what you would grind here is the fabled Tubalcain grinding on his lathe. Note too that he is using his compound to grind the angle:

http://www.youtube.com/watch?v=IHNLSnFSKrM

Jaakko Fagerlund
04-21-2014, 06:34 AM
so why would you actually want to grind on a lathe? because work is hard? you can hardturn. to get a better finish? when you do it right, you get mirror finish when turning. and didnt someone just mention, he was polishing the ground surface? because you want more precision? where would that come from. grinders are built to precision levels 2 - 3 x higher than lathes.
Many reasons, surface roughness being one. You just can't turn a smooth surface, you can easily feel ridges even with your fingernail in there. And you can't turn some forms or contours or shapes with ceramic inserts, because the insert doesn't fit in there or the amount required for removal is too small for turning.

Good example of a place where a turned surface gives issues is mold guiding parts. They give out a nasty sound and do not have much bearing area, but if they are ground all the scraping sounds and air whistling goes away and they just last longer.

Polishing a surface has nothing to do with precision itself, you can polish any shape and contour you want.

And you can get precision from a lathe also, it is basically like a cylindrical grinder. I mean that if you can turn cylindrical round objects with it (lots of forces involved), then you definately can also grind them with it (much less forces involved). Sure it is not meant for it or is not the most ideal, but it can be used for it. The same thing in milling ith a lathe - not meant for it, but can be done.

Don't dismiss work methods just because you don't have a use for it or don't know all the possible situations that would require it.

dian
04-21-2014, 08:18 AM
that video makes me sick. from using my deckel s1 grinder, that doesnt (yet) have vacuum conected, i know the dust goes everywhere and quite a distance too. im sure a lot of it went straight through that old coat. it would take me two days to clean the lathe and everything else. (does everybody have this cap for the collet?) i could only see myselsf do this with cbn. if i really had to.

"You just can't turn a smooth surface, you can easily feel ridges even with your fingernail in there": jaakko, you dont really mean that, right? if i run a carbide insert at the right speed, the surface is as polished.

besides, why does any decent grinding spindle have p2 bearings. because you can do it with motor bearings as well? btw, if you take an angle grinder, you can mount it to the toolpost, dress the wheel and get decent results, as they tend to have angular bearings

J Tiers
04-21-2014, 08:38 AM
Dian... perhaps you would be happier over at "Practical machinist".

Most people here do not have machines which can run a high rpm/sfm AND at the same time take a cut which will allow a carbide tool to give a smooth surface. The power and rigidity are just not there.

Some DO have that type machine, but I wager most do not.

The options then are grinding, or grinding, or maybe grinding.

Yes, bearings are not "that" different in precision, once you get into a decent one to begin with... probably less than a 10:1 improvement from a reasonable cost good bearing to the most expensive ones you can credibly buy without a special order. The required precision may make the expensive ones necessary. or not.

I question whther angle grinder bearings would give good results, but part of that is likely to be that the whole grinder is made for rough service, and not for precision. The bearings are probably not the limiting factor.

dian
04-21-2014, 10:45 AM
my 20 years old, chinese 3-in-1 does it.

happy grinding.

John Stevenson
04-21-2014, 11:19 AM
My 20 years old, Chinese 3-in-1 does it.

happy grinding.

That does it, he definitely wouldn't fit in over there. The gnomes of Zurich must be turning in their graves [ or should that be grinding ? ]

Jaakko Fagerlund
04-21-2014, 01:07 PM
"You just can't turn a smooth surface, you can easily feel ridges even with your fingernail in there": jaakko, you dont really mean that, right? if i run a carbide insert at the right speed, the surface is as polished.
Yes I mean that. Even with a CNC lathe (Nakamura Tome if you must ask) it just isn't happening. There will be ridges from turning, because what you are basically oing is a very very fine thread (there is certain feed rate per revolution, aka thread).

I do know what you mean by your so called "polished" surface, easy to get on basic steel when you go pass 180 m/min with the surface speed when running with carbide tools and proper feed and DOC. But the surface is not smooth, it just looks nice.

Next time run your finger nail over it and you will feel those ridges. Or drag any piece of steel sheet edge over the surface and you will hear that there is ridges.

plunger
04-21-2014, 01:36 PM
:)Brian I was trying to throw you a compliment.I have often wondered how much damage is done by using emery on a lathe to get a polished finish. I would also wonder in a home shop environment why a toolpost grinder would be justified, although I would love to have one but never manage to get that" YOU SUCK" scenario.
I suppose doing things like internal grinding on tapers like collet holders or perhaps hardened steel would be where it would be useful.Maybe an air grinder would need that type of precision?Perhaps one would need a toolpost grinder to make a high precision spindle for a toolpost grinder?:)

mrriggs
04-21-2014, 02:05 PM
I have done the angle grinder in a tool post trick once. Had to turn down a 530 sprocket to fit a 520 chain. It was a hardened sprocket and the interrupted cut destroyed carbide cutters. The bike had to be on the road the next day to get me to work so I broke out the angle grinder.

http://www.gofastforless.com/junk/OffSet04.jpg

I don't recommend this method but desperate times call for desperate measures. The chuck got a thorough cleaning afterwards. I didn't worry about the rest of the lathe, it's a junker.

stanger53
04-21-2014, 06:00 PM
In my work, I have a lot of spools that need to be turned down and polished because they are rust pitted or scratch where they slide through a seal. We are talking about .50" dia and about .75" length, hardened steel.

I had a regular machine shop do this for me, but they cam back very grooved - much worse than a modern phonograph record surface.

When I got my little 7x10 mini-lathe, I tried doing the same job, but I couldn't get a much better surface than I got from the machine shop.
I had heard that these parts were probably originally ground to surface, so when I saw the small tool post grinder available for my lathe, I picked one up and set it up.

It grinds much smoother and easier and left a finish, while not polished quality, was a very fine brushed surface. Running your fingernail across it was like dragging your nail across a sheet or paper - there was drag but no grooves. A quick hit with 600 then 1000 grit paper produced the near mirror finish I needed so the spool would slide smoothly through the seals.

A friend of mine has a much larger lathe that is more rigid and powerful, and he has seen mine work and tried his luck at turning the same type of part on his lathe with a carbide insert.

He said the finish it left was about comparable to what I had after polishing, so for him and his machine, a grinder would not be needed for the job.
For me, it was.
I suspect that my larger 3-in-1 machine, properly setup, would do a similar job as his.

As for grinding dust, even after grinding both ends of dozens of spools each year for several years, I doubt 1/32 inch of material was worn off of my grinding stone, so there wasn't much material distributed on my machine. I kept the bed clean and brushed and vacuumed it as needed and don't see that there was enough contamination to cause excessive wear from the grinding material

loose nut
04-21-2014, 06:26 PM
Yes I mean that. Even with a CNC lathe (Nakamura Tome if you must ask) it just isn't happening. There will be ridges from turning, because what you are basically oing is a very very fine thread (there is certain feed rate per revolution, aka thread).

I do know what you mean by your so called "polished" surface, easy to get on basic steel when you go pass 180 m/min with the surface speed when running with carbide tools and proper feed and DOC. But the surface is not smooth, it just looks nice.

Next time run your finger nail over it and you will feel those ridges. Or drag any piece of steel sheet edge over the surface and you will hear that there is ridges.

Well, he ain't wrong.

Jaakko Fagerlund
04-21-2014, 06:42 PM
Well, he ain't wrong.
Sorry, about what?

J Tiers
04-21-2014, 08:59 PM
my 20 years old, chinese 3-in-1 does it.

happy grinding.

Good for you. The 20 year old 3 in one is probably powered by a large motor. Try that on the typical Atlas lathe that so many here have and we'll see how well it works. 20 years ago that imported stuff wasn't too bad.... they have learned how to make it cheaper now.

If I ever get the Rivett finished, it was *intended* for grinding, among other things. Rivett made grinding accessories specifically for their lathes. But after putting all the work into it, I wonder if I would ever do it.... probably not.


Grinding has been banished to another room on a purpose made grinder. So, yes, grinding is happy.

dian
04-22-2014, 04:50 AM
good man.

J Harp
04-22-2014, 06:15 AM
Some time ago I saw a you tube of a toolpost grinder that a fellow (An Englishman I think) had built for grinding parts for a model v8 or v12 automotive engine he was building. He used tapered bronze bearings lubricated by one teaspoonful of light oil which was recirculated. He said the grinder was good for several thousand rpm.

There was a separate video showing the engine he built running. I have searched every way I can think of and have not found those videos. Does anyone recognize what I'm talking about and have a link?

With Brian's abilities he could probably build a grinder of that sort, then he could really slick those crank journals up.

Cuttings
04-22-2014, 01:11 PM
Hi Brian
I just took a look at the B2227L on Busy Bee's web site.
Looks like the tool post may mount on the compound similar to my B2229 mill lathe.
I built a mount out of aluminum to hold my electric die grinder.
So far it works quit well. I recently ground the jaws on my three jaw chuck to take out some taper and it did a good job.
If your interested I could post a picture later.
Have to head out to get my new hearing aids this morning.
By the way, I haven't heard anything about the water level there lately.
You must be keeping your head above water OK.

dian
04-23-2014, 04:17 AM
i have saved a video similar to what you are describing and its not there any more. i remember, he did not really explain the bearing setup, though.

dian
04-23-2014, 11:28 AM
Yes I mean that. Even with a CNC lathe (Nakamura Tome if you must ask) it just isn't happening. There will be ridges from turning, because what you are basically oing is a very very fine thread (there is certain feed rate per revolution, aka thread).

I do know what you mean by your so called "polished" surface, easy to get on basic steel when you go pass 180 m/min with the surface speed when running with carbide tools and proper feed and DOC. But the surface is not smooth, it just looks nice.

Next time run your finger nail over it and you will feel those ridges. Or drag any piece of steel sheet edge over the surface and you will hear that there is ridges.

o.k., i was curious and just did it. i took some steel and took a 2mm doc at 225 m/min (would have had to change belts to go faster) on the 3-in-1. when using the slower feed, i indeed got slight ridges. then i feeded much slower manually and the surface was dead smooth. after hitting it with 1200 grit emery for five seconds, i have never seen anything shinier.

btw, im pretty sure i could get the same results with a hss round finishing cutter (ifanger) at 25 m/min.

Jaakko Fagerlund
04-23-2014, 03:53 PM
after hitting it with 1200 grit emery for five seconds, i have never seen anything shinier.
1200 grit? You should be able to see your reflection from the workpiece at that point without much distortions :)