3/8" 24 tpi UNF to 3/4" 16 tpi male-to-male adapter

baldpate · 12 Jul 2012

Hi,

I have a small home-made lathe driven by an old Black & Decker drill (sensitive woodturners should look away now

). The business end of the drill has a 3/8" 24 tpi UNF threaded hole (the 1/2" capacity chuck has a corresponding threaded male stud; this is unlike most modern drills, I believe, where the chuck is female, and the drill male).

Anyway, I have been pondering for some time how adapt the business end of the drill so as to end up with a 3/4" 16tpi threaded male stub. This would allow me to take advantage of a whole range of goodies designed for the small Record lathes. I've found plenty of ways of of getting from 3/8 to 1/2" (this seems to be the other commonly used thread on drills), but nothing which will take me all the way to 3/4".

So ... I'm looking for a 3/8" to 3/4", male-to-male, UNF adapter; if necessary, though, either end could be female - I'd just need to add threaded rod to the female end.

Has anyone any bright ideas, please? My metalworking skills are pretty limited, so the solution would have to be pretty-much off the shelf.

Thanks

Chris

CHJ · 12 Jul 2012

I would think trying to place the loads resulting from using lathe goods designed to fit a 3/4" thread onto the nose bearing of the drill would be most unwise.
I have an old metal bodied and gearbox B&D drill with that nose configuration and no way is it suitable for anything other than a standard drill chuck.

baldpate · 12 Jul 2012

Chas - do you mean it's dangerous, or just likely to bust the drill? If it's just the drill, I have several of them & no other other use for them, so I'll take the chance. If you mean it's seriously dangerous, I will bow to your greater experience and desist.

CHJ · 12 Jul 2012

The loads you are likely to apply risk being too much for the little nose bearing, if you attempt to fit something like a standard wood lathe chuck then I would say you are moving into a danger zone with the speeds delivered by the drill and the energy involved if something lets go.