You have a lathe that was produced by Double A with a 1/2"-20 Spindle Thread. Any Sears lathe with a stock number starting with 109 was made by Double A. They made this lathe only for Sears and did not supply it to anyone else. When they went out of production Sears bought all of the spare parts and pieces they had. There are no remaining parts available. You can get a 0 morse taper dead center, a 3 and 4 jaw lathe chuck produced by Sherline and the gear set produced by Clausing.