I am not very mechanically adept, so I have to rely on the inspiration of more mechanically gifted people...
Somewhere I read about someone making tuners from eye bolts, but saw how it was done.
I don't think the thread 'pitch' (1/4-20, 10-32, etc) in threads per inch does anything at all for 'gearing'. All I can visualize is two nuts 'jammed' together after the bolt passes through the headstock to keep the bolt attached, and it would thus be 'direct' tuning 1:1, kind of like violin pegs.
I've seen it proposed to use pegs on an archtop guitar before...many acoustic basses use gears tuners, I don't know about cellos, but violins, violas and some ukes (smaller, I guess) use friction fit pegs. I imagine geared tuners on a bass are a modern evolution as Stradivari and others were wood-workers, not machinists ;O).
I have some unique cabinet pull knobs I want to use as tuner keys...they are threaded 8-32 or so but that's not the biggest issue.
Some way of using them as tuner 'buttons' is what I would like to to...the eye bolt tuner idea came to mind, but hacking them onto standard geared gear tuners might be the best Murray-rigging I can muster.
DID NOT see how the eye bolts were used...
Is there a way to edit one's errors after posting here? (Sorry, used to work at a newspaper...can't help it).
I just found a 15 minute timeout edit feature for THIS post, but not the one I made the original error in minutes earlier :O(