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View Full Version : Small lathe grinder for grinding IDs cheap/improvised



KEJR
04-24-2010, 12:11 PM
I'm looking for a grinder that can grind ID's on a small lathe. Has anyone come up with something that can be improvised off of an existing tool within HSM grasp, perhaps a bit more precision than a dremel tool?

Spin Doctor
04-24-2010, 12:29 PM
I do remember an article for a tool post grinder powered by a laminate trimmer. Maybe 12 years ago????????????

Paul Alciatore
04-24-2010, 12:45 PM
Well, first you ask the question and then you kill the obvious answer. Aaaaagh!

So, what's wrong with a Dremel? I have used them, strapped to a tool holder in a lantern style tool post with hose clamps and it worked just fine for grinding chuck jaws.

http://img.photobucket.com/albums/v55/EPAIII/ChuckGrind1R.jpg

http://img.photobucket.com/albums/v55/EPAIII/ChuckGrind9R.jpg

I did use a Dremel brand tool. I'm not sure if an import, knockoff tool would work as well, but who knows, some may even be better.

I believe some have used the hand held die grinders for the same thing. Again, quality will vary among the different brands and you may just get what you pay for.

One caution here would be to be sure to dress the stone after mounting whatever grinder you mount. It is almost impossible to perfectly align the grinder's axis on the toolpost and the stone in the grinder so this step automatically takes care of any misalignment that will surely exist. Diamong dressing tools can be purchased for reasonable prices if you look around. You will have to improvise a mount on the lathe ways and move the rotating tool back and forth across it using the carriage cross feed to feed it into the stationary dressing tool.

And be sure to cover your lathe well for any such operations to keep the abrasive dust out. See my second photo.

Dr Stan
04-24-2010, 12:48 PM
I believe some have used the hand held die grinders for the same thing. Again, quality will vary among the different brands and you may just get what you pay for.

I've used a Dayton electric die grinder for this very purpose. Follow Paul's advice regarding dressing and protecting your lathe.

CountZero
04-24-2010, 12:52 PM
I like the foil for covering the ways, I have been using towels and are always a bit anxious of them getting caught.

Ron of Va
04-24-2010, 02:06 PM
You don't have to mount the Dremel tool itself. You can just use the wand attachment in a tool holder. (the ways were covered before the grinding began)
http://www.hunt101.com/data/500/medium/ChuckGrinding.jpg

kc5ezc
04-24-2010, 02:42 PM
Ron: Good idea on the Dremel handpiece. That is the old style handpiece. The new one is 'ergomonic', covered with a glob of stuff. Don't know what is under the stuff.

38_Cal
04-24-2010, 03:54 PM
Last Dremel I had apart a few years ago had a piece of plastic aquarium tubing between the motor and the threaded collet shaft, to act as a combination universal joint and shear piece. Problem was, danged thing kept shearing in normal use. I'm now using a Black & Decker and (knock wood) have had no problems with it over five years. If I were going to grind chuck jaws, I would probably rig up my Foredom flex shaft tool's handpiece over a Dremel type tool.

David

Farbmeister
04-25-2010, 04:31 AM
I saw this before (another board) and I don't know why you would do this with a dremil.

The bearing (most likely bushings) have poor tolerances and the lack of support would have the stone vibrating all over.

How can you expect to hold any reasonable tolerance that a boring bar would not more easily achieve?

Black_Moons
04-25-2010, 05:24 AM
Farbmeister: Well, for one, boring bars don't do well touching up hardened jaws. unless you wanna run a few 1000 SFM and those super hard super expensive inserts like CBN

radish1us
04-25-2010, 11:26 PM
Farbmeister: Well, for one, boring bars don't do well touching up hardened jaws. unless you wanna run a few 1000 SFM and those super hard super expensive inserts like CBN


Big difference from crashing into the jaws, as to just taking a lick off them, to true them up.

Most jaws ARE hardened, but how hard is the question, now go find out how hard replacable tips are. When you find out, let me know what the numbers are.

So before firing of an answer while your only half cocked, go try it out, use the same techniques as you would to load up soft jaws, ONLY take a very light lick over the hard jaws. So what if a few sparks appear, but the jaws will be trimmed to run DEAD TRUE at that size. Then go cut some metal with the exact same tip.

You will be surprised with the results.

KEJR
04-26-2010, 02:03 PM
OK, so I won't trash the dremel idea. I have one available so I maybe should consider it. The remote handpiece solves my concern regarding mounting the thing rigid, but I don't have one of those on my dremel. I did find out on the web that another guy mounted one of those cheap pneumatic "mini die grinders" or "pencil die grinder". It was nice because he made a sleeve that fit a 3/4" boring bar holder.

The reason I want to grind is that my lathe is not the most rigid thing in the world so to accurately take off a thou or two in hardened steel with a boring bar is probably going to be a challenge. I want to re-machine a taper for a ER40 collet chuck (in place) on a 1940s vintage logan lathe. The lathe has a 1.5"x8 threaded spindle, and the face on it runs out a couple tenths. I'd like to mount the chuck and machine it in place with a fine finish. I might try a boring bar first as I can always go a little deeper and grind it if it doesn't clean up nice.

Thanks to everyone!

Ken

rowbare
04-26-2010, 02:05 PM
http://img.photobucket.com/albums/v55/EPAIII/ChuckGrind1R.jpg


I was wondering where my hat went!:D