Not exactly a homemade tool but adding a Gibraltar rotating handle (Enco part #319-7676) to the lathe cross slide control handle is a great improvement to the lathe operation. I thought adding the rotating handle with a ¼-20 threaded end was going to be an easy addition to my 12” swing geared-head lathe. I discovered the original handle was a press fit into a hole too large to accommodate the ¼-20 thread and the next larger size in Gibraltar handle with a larger thread is too big.
I solved the installation problem by enlarging the upper section of the hole in the cross slide control handle for a press fit 21/64” dia. homemade threaded insert. In addition, drilling a deeper concentric hole (but not a thru hole) into the control handle with a #7 drill allows taping another three full ¼-20 threads near the hole bottom. While the larger lathe awaited its improved cross slide handle, I used my smaller 3” swing Unimat SL lathe to machine the insert. The ¼-20 internally threaded insert is 0.225” deep x 0.329” dia. and made from stainless steel 303 rod. A combination of a press fit and Loctite 680 holds the insert in place and then using a bottom tap completed the bottom threads.
I plan to install two of the smaller 10-32 threaded Gibraltar rotating handles for the lathe compound control handle and will have to use the same technique.