The knob for the spindle control lever was missing on my used 12”x37” geared-head lathe when it arrived. So I used some artistic license in designing the 0.75” dia. by 1.55” long replacement knob. It is made from 12L14 steel and internally threaded with 3/8-16 thread (and not M10x1.5 considering this lathe was built in Taiwan in 1987). I used a clamp-type knurling tool for the 21 pitch diamond pattern knurls.