WTB Mitutoyo No. 75 radius gage .650"

[MyLilMule]

I bought an old Mitutoyo No. 75 radius gage set at auction and it was missing the .650" gage. Perhaps someone out there in the interwebs has a loose one they would be willing to part with.

PFA of a .800 gage from a similar set:

 

[Bone Head]

Don't have one; sorry. But if you have a need for a .650 contact Mitutoyo.

 

[MyLilMule]

Don't have one; sorry. But if you have a need for a .650 contact Mitutoyo.

Normally, I don't buy tools until I need them. But this came in a lot at auction really cheap, and it would be nice to have a complete set, so when I do need it, I have it. I'm sure Mitutoyo will gladly sell me one for 10 times what I paid for the rest of them. I see other sizes on eBay. Maybe one will come up.

 

[woodchucker]

My Starrett set is in fractional, not decimal. Never knew they existed that way. it's not a fractional size, nor a metric conversion size.
Good to know, but not sure I know why.

 

[MyLilMule]

My small ones are fractional. These are .500 to 1.000" in .050" incremets.

 

[RJSakowski]

I would be tempted to make one.

It shouldn't be too difficult with an RT. A piece of cake with a CNC mill. Lacking either, a boring head can make the inside radii. For the outside radii, I would cut a full circle and mount sections to the gauge body.

 

[Dabbler]

For the outside radii, I would cut a full circle and mount sections to the gauge body.

A one-piece outer radius can be done with a manual boring head after the inner radii have bee cut. You can turn your tool to scribe the outside, and then by hand rotate the cutter 180 degrees, move down a few thou, and then repeat. for a 35 thou stainless plate this doesn't take very long and leaves you with a professional looking gauge in the set. In regular steel it is even faster.

 

[woodchucker]

A one-piece outer radius can be done with a manual boring head after the inner radii have bee cut. You can turn your tool to scribe the outside, and then by hand rotate the cutter 180 degrees, move down a few thou, and then repeat. for a 35 thou stainless plate this doesn't take very long and leaves you with a professional looking gauge in the set. In regular steel it is even faster.

Dabbler, I would like to understand what you are saying.
Are you saying just scribe using the boring head, and cut manually?
or are you defining an operation where you cut using the boring head?

 

[Dabbler]

You can cut the material with a tool ground to cut the outside of an arc. You can cut away in very thin cuts, using your hands and traversing through the 180 degrees. This is if you don't have a rotary table, and don't want to buy one for this particular operation.

You use it like an engraving tool, taking .002 deep cuts in SS or about .003 cuts in mind steel. It has been 30 years since I've had to do this, but when I did, it worked out fine. For my boring head with a 1/2" tool size, I inserted a 1/2" bar in the horizontal hole and use it to power the cut by rotating the boring head by hand. It worked surprisingly well at the time, and I had the time to do it way back then.