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.

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.

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.

Karl

In article , Jeff says...

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.

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.

Jim


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