Posted by Bill Dornfeld on May 25, 2001 at 16:30:25:
In Reply to: south bend thread cutting gears posted by Gale Hansen on May 20, 2001 at 12:50:59:
I have an old Sheldon lathe that has a mix of original Sheldon and Boston Gear gears. All of the gears in the train have to have the same pitch (mine are 16, I believe), so once you figure the pitch of your gears, you should be able to visit a Boston Gear catalog. (try www.bostgear.com) You can determine the pitch (technically, the "diametral pitch") by dividing the number of teeth on any gear by the pitch diameter - a diameter running through the midpoint of the teeth.
If you are lucky, the bore and keyway of the gears will be standard and you'll be on your way. Otherwise, there is always e-bay!
Good luck.
Bill Dornfeld