Chuck Key for South Bend 4 Jaw

I recently purchased a model # 4006 South Bend 6" four jaw manual lathe
chuck which as made by Skinner Chuck Co. It came without a key. I though it
would be simple to find a replacement; however, I now discover that a
standard 5/16th" square key does not work because the key slot is not
square. The corners of a 5/16" square key need to be chamfered to fit the
slot. Does anyone have a resource for this key. I've temporarily altered a
standard 5/16" key, but I want the right key so that I won't "bugger" the
key slots.
Jeff T.
Reply to
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FWIW, I had to do the same thing - 10 years ago. Its never hurt the chuck. I did work carefully on the key grinding to make it fit close.
Reply to
Karl Townsend
I've found a nice way to do this, simply turn the end of the key blank down so the diamter is slightly less than the corner-to-corner distance on the square. Then mill it square and the result will be radii on the corners to fit the broached hole in the chuck adjusting screw.
If you want to see what diameter to turn it to, ID mike the adjust screw bore at the largest size.
Reply to
jim rozen

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