# Radius grinding a lathe tool



## gld (Dec 27, 2011)

Most of you have probably all ready thought of this, but here goes.


Today I needed a 1/16 radius on a 1/8 lathe tool.. So here is how I did it.
I put a Dremel flex shaft thru the lathe spindle and clamped in the lathe chuck. Then I made a stand for my ball turning tool, milled for a 5 degree relief angle and slotted for the 1/8 tool. It may not be perfect, and it was slow going, but it sure did a good job.


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## smfr (Dec 27, 2011)

Oooh, good use of the ball turner!

I'd probably have covered the ways with paper to avoid getting grit everywhere, but this certainly is a handy trick!

Simon


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## gld (Dec 27, 2011)

Yes the lathe was covered....the pictures was an after thought.


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## Maryak (Dec 28, 2011)

Guys,

With a little bit of practice the easiest way is to use a radius gauge and your bench grinder with a fine grit wheel. 

IMHO unless the radius needs to be spot on, (which is not often the case), just drill the appropriate sized hole in a piece of thin plate and cut out a quadrant which gives a poor mans radius gauge.

Hope this helps.

Best Regards
Bob


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## Tin Falcon (Dec 28, 2011)

I agree with bob grind them by hand saves time. 
Tin


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## gld (Dec 28, 2011)

Well, I've tried to grind by hand, and they just never looked right. From now on I'll ruff it out by hand and finish with the ball turner,and they should by dam near perfect. IMHO anyway.. ;D


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## rustyknife (Dec 28, 2011)

I approve making a tool to make a tool ;D.....some of the most complicated things may the very best artwork.

Regards
Eric


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## Tin Falcon (Dec 29, 2011)

Gary use what works for you.
Tin


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## Herbiev (Dec 29, 2011)

Thanks Gary. Great tip. :bow:


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## GailInNM (Dec 29, 2011)

Gary,
Thanks for posting your method. 
Like some of the others I used to free hand grind such tools and they were adequate for the job. With increasing age and visual problems I use a a technique similar to yours on a tool grinder and get better results. Your method adds one more way to do it for those of us who are not happy with their freehand results for what ever reason.
Gail in NM


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## Ken I (Dec 29, 2011)

Hmmm.....I don't have a ball turner (yet) - another good reason for me to make one.

Nice tip.

Here's one in return - file a diagonal groove in a shank - silver solder a piece of drill shank or silver steel of the right diameter and quench - sharpen (a'la tangential tool) - crude but effective - gives an ellipse therefore not a true radius.

Ken


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## compspecial (Dec 29, 2011)

Very clever,Gary, could be a handy setup for lots of jobs!
                       Stew


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## purpleknif (Dec 29, 2011)

I've been known to use a ball mill.


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