Tool Post Grinder -

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davestea
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Tool Post Grinder -

Post by davestea » Sat Feb 22, 2003 9:34 pm

I have an older Unimat spindle and motor that would make a great toolpost grinder for the Smithy lathe. All I have to do is make the adapter for the tool post.

I have read a lot of posts about tool post grinders do's and don'ts and all but do I really need one? I guess if I have to ask then I don't need one - huh? But let's say I do and don't know it - what would I use it for?

As you might guess I am rather new to all this.
Dave
Smithy 3in1, Select Mill, Atlas 6" lathe

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Doug_C
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Re: Tool Post Grinder -

Post by Doug_C » Sun Feb 23, 2003 12:15 am

Hi Dave,

Since you have it, I'd say it is more of a convenience than a need currently. Consider it another option that may be handy in the future.

These can be used to cut harder materials than can be turned via single point tooling. A superior finish can be achievable for reduced wear with greater bearing surfaces to spread out loads along with finer dimensional control for tight tolerance work.

I have heard, with some experience one can do endmill flute sharpening on small lathes with a low friction free wheeling spindle.

A bit of imagination can find many useful solutions if one is motivated enough.

The light duty may test your patience. It might not spin fast enough or have enough power with reasonable sized wheels to make decent headway.

Some things ya have to live with, or live without. Make do or sell it off and use the funds to make something else do? [img]/ubb/images/graemlins/blush.gif"%20alt="[/img]

DC

Butch
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Re: Tool Post Grinder -

Post by Butch » Sun Feb 23, 2003 1:56 am

It's just one of those things that are nice to have when you need it. I built mine several years ago and have only used it half dozen times. I couple weeks ago I needed a small keyway cutter for a project I doing. It worked just fine for cutting down an endmill to make the cutter.
Have also used it to regrind centers . Go ahead and build it, when you do need it, you'll be glad you have it just like a lot of other seldon used junk we keep around.

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JimGlass
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Re: Tool Post Grinder -

Post by JimGlass » Sun Feb 23, 2003 8:57 am

Hi Dave;

My shop is full of stuff built from components that were discarded by my employer. I cannot think if anything I regreted building. Sooner or later it all gets used and usually makes a little money at the same time.
Jim
Tool & Die Maker/Electrician, Retired 2007

So much to learn and so little time.

www.outbackmachineshop.com

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len
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Re: Tool Post Grinder -

Post by len » Sun Feb 23, 2003 1:05 pm

Dave,

I have an EMCO toolpost grinder for my V10P that uses the Unimat spindle. Mind you that this is an official EMCO part. So it seems your idea is a good one. How do I know it's a lathe spindle? Well, I used to own a Unimat, so I know what it looks like, but the real clincher is that it has rack teeth milled into it and a slot for a grub screw, just like the Unimat spindle.

The problem with any toolpost grinder is the abrasive dust it produces. A lot of people won't tolerate that on their lathes. If you can live with that, then it's a useful tool for getting bearing finishes on shafts or bores. For best results, you have to dress the wheel with a diamond tool clamped to your lathe chuck (with spindle locked) before each use.

Oh, yes, my advice is to build the grinder. I think the motor will have enough power for most grinding jobs. On the other hand, you could probably fetch a nice sum on eBay for the part.


len

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davestea
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Re: Tool Post Grinder -

Post by davestea » Sun Feb 23, 2003 4:39 pm

thanks people - appreciate the ideas.

And, I guess I will build it. I don't use the Unimat much any more - is great for doing the small stuff tho. And I would not sell it off - I'm a keeper. Ya, I do know how it is with all the stuff we collect and build. I am in the process of using the boring bar holder for my QC tool post (just short of 3/4" diameter hole) as a base for a ball turning tool. Will use a small boring head with a crank of some sort at the end of the boring head shaft. The offset of the boring head will give me the different diameters for the shaft end balls.
Dave
Smithy 3in1, Select Mill, Atlas 6" lathe

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Bryan
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Re: Tool Post Grinder -

Post by Bryan » Sun Feb 23, 2003 7:52 pm

The way I have (and continue to) look at it, is this:
"The tool you've got, is the tool you can use... if you don't have it you can't use it!"
By getting or making a tool, even if only for one job, you have expanded your capabilities to do future jobs... if you can't write off the cost to the first job, it will no doubt pay for itself in the long run, even if only as a tax deduction (if not purely for hobby use)...
[b]Bryan[/b]
[i]"Simplicity is the ultimate sophistication."[/i] Leonardo da Vinci (1452-1519)

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Orrin
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Re: Tool Post Grinder -

Post by Orrin » Mon Feb 24, 2003 11:24 am

I have a toolpost grinder and have used it on a job that IMHO could not have been done without it. I had to clean up a case-hardened lathe spindle that had been badly scored.

I seriously doubt carbide cutting tools could have done the job. Because of the way it was damaged, the carbide would have had to made an interrupted cut and would most likely have fractured.

As mentioned in another post, you'll need a diamond dresser for the wheel. I held mine in place with a mag-base dial indicator holder.

If you use your TP grinder, you'll have to cover every piece of precision equipment in your shop. I used plastic sheeting with cloth dropcloths on top of that. (The cloth holds the grit. If you use only plastic, the grit will slide off onto your equipment when you start uncovering things.)

Plastic grocery bags work well to encapsulate your chuck, cross slide, compound, tailstock, etc. Use plenty of Tom Ridge tape to hold everything in place.

Even though your heaviest pass may be only two ten-thousandths of an inch deep, grinding produces heat that can distort your work piece, especially if it is an interrupted "cut." I hold ice cubes on the work piece to keep it at a constant temperature.

Let me explain. If one side of your work piece gets warmer than the rest, it will bow toward the grinding wheel. This results in a deeper cut which produces even more heat and even more bowing. It's best to take measures that keep the whole piece at the same temperature.
So many projects, so little time.

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