Using a spindle crank to thread on a lathe ?

[savarin]

Ha Ha, luck I think. There will be some backlash in the lead screw which will place the tool bit in a different place usually.
I always back off before returning

 

[Alcap]

Following ideas from HM I made my spindle crank , handwheel for now . I got it from Amazon , the stock I had was close to finish size so it didn’t quite clean up , turned the end and milled a key way slot . I didn’t like the parting line on the outer edge of the wheel so I filed and sandpaper it , gave it a better feel.

 

[Alcap]

Made a bracket to mount the handle . Made a slot in the end so the center bolt can just be loosened.

 

[homebrewed]

If cutting threads that are the same as or coarser than the lead screw threads, the mechanical advantage of the spindle-to-LS connection gets worse and worse. To address that, some folks have added a hand crank to the lead screw and turned that instead. In that direction you're taking better advantage of the change gear reduction ratio.

This kind of mod is fairly easy to do on mini lathes. I've done it (although not for cutting really coarse threads). I can't speak with any authority regarding the mod on bigger lathes.