Ramblings of a Rookie: making a square-hole collet

AJB

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Joined
Oct 27, 2020
Messages
26
A month or so ago I bought a graver sharpening fixture that uses collets. The problem was that I am using square gravers and a DIY pneumatic hand piece that does not use collets.

I found that making a collet with a square hole is actually not very difficult. While I used a lathe to make one, I think it could probably be done with hand tools.

The process involved starting with a brass collet blank that was drilled all the way through. The rear 2/3rds was drilled out to 1/8” for a pilot hole, and the front half to just over 0.1”. A blank 3/32” graver was then squared to sharp edges on one end and that end was inserted into the back of the collet. The 1/8” hole allowed it to align squarely. The face of the collet was then placed on a firm surface and a graver hammer was used to tap the graver through the front of the collet. The graver cut the square hole to perfect size.

After drilling and tapping for a set screw, the process of driving a graver through the collet had to be repeated to remove the burr that was raised by drilling a tapping.

The final step was to cut the grove that indexes the collet in the graver sharpening fixture. The collet was inserted in the graver sharpening fixture, which was then set to 45 degrees. The graver and collet were then turned into alignment. Then the location of the slot was marked on the collet and cut.

The final step that was unnecessary in my case would be to insert a short plug in the rear of the collet and bond it with high strength Loctite.
 

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AJB

Member
Joined
Oct 27, 2020
Messages
26
Thanks Allen. My purchase of a fixture that required collets was a rookie mistake! I was surprised that no one makes collets for 3/32” square gravers, so I had to adopt.
 

AJB

Member
Joined
Oct 27, 2020
Messages
26
Allen,

I saw those, but wasn’t sure how repeatable they would be as tools were inserted and removed for sharpening only. If the DIY project hadn’t worked out, that was going to be the next thing tried.
 

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