Thanks Robert, so you are saying that my machine is probably a 1959 vintage? I will try to obtain that catalog, if it doesn't work than I would be greatful to have you e-mail me one. I see the fault with my measurements of the threads. You'll have to pardon my ignorance, next semester is my threading on the lathe class. I obviously don't have 1" of clear thread in the spindle nose. So I took my digital caliper opened the jaws .500" and counted that one jaw was exactly on the peak of one thread and the other jaw was on the peak of the 6th thread. But the first thread would actually be thread zero. When I took my 5R graduated 6" rule I saw my error the threads were falling exactly on the 10ths. Thus as you said 10tpi. That gives me more options for chucks. I would like to find a 4 jaw when I have some spending money.