# Thread: 5c collet fixture - name & use?

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## 5c collet fixture - name & use?

I bought a 5c collect fixture at an auction and the fixture in images was lumped in with the item I wanted. What is it, how is it used? Why is the angled surface on the underside a compound angle? I'm trying to find out if I should keep it.

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It's for sharpening endmills on a surface grinder. The angles on the bottom correspond to the relief angles on the ends of the endmill. Nice score

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it's for sharpening the ends of end mills on a surface grinder. The angles are for relieving the cutting edges - one is for the 1-2deg angle from tip to center and the other is (I think) 7deg for back relief behind the cutting edge. The divisions on the collar are possibly for different numbers of flutes, though the numbers seem kinda high!

edit, doh, too slow!

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The numbers make perfect sense. It is divided into 8 and 12 divisions. Some of the marks are shared by both of those and others are only for one. Eight divisions give you 2, 4, and 8 flutes. Twelve divisions give you 2, 3, 4, 6, and 12 divisions. So, together they give you 2, 3, 4, 6, 8, and 12 divisions. You just have to skip ahead to the appropriate line on the group you are using.

Five and ten are the most noticeable missing numbers of divisions, but you can't have everything. Many countersinks use 5 flutes, but then they are not usually evenly spaced anyway.

Originally Posted by mattthemuppet
it's for sharpening the ends of end mills on a surface grinder. The angles are for relieving the cutting edges - one is for the 1-2deg angle from tip to center and the other is (I think) 7deg for back relief behind the cutting edge. The divisions on the collar are possibly for different numbers of flutes, though the numbers seem kinda high!

edit, doh, too slow!
Last edited by Paul Alciatore; 09-12-2019 at 09:48 PM.

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Take that silly hex collet out. It just confuses the issue.

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Nice bit of kit...... if you have a surface grinder, otherwise pretty useless.
However, if you don't have a surface grinder, send it my way, i will happily pay USPS.

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Originally Posted by CalM
Take that silly hex collet out. It just confuses the issue.
Ditto on that! The last user may have been making a punch die or something. Don't really know why it was in there--Maybe it was the only 5C collet he had that would fit the end mill or tool he was trying to hold. I've done that with metric crap.

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Thank you all for your responses.

CalM:
I put the hex collet in there because then the transition between the fixture and the collet would be obvious (was not certain that the fixture would be distinct in a phone camera image) - since I had no idea as to what the fixture was used for, I did not realize that the hex collet would be inappropriate.

thaiguzzi:
Since I have not acquired a surface grinder, the fixture is fairly useless to me. Maybe someday I'll have a surface grinder.

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