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.