I am in the process of overhauling/restoring an older Atlas/Craftsman lathe and i have a question regarding the spindle. On the pulley and gear assembly there is a screw, is this just for oiling the bushings or is it a set screw? if it is tightened all the way up it will not allow the pulley assembly to spin freely when you disengage the pin from the back gear. (I'm guessing it is just an oil port). Also is there a minimum clearance between the Back gear and the pulley? Thanks in advance.