So I really like the idea of taking non-musical parts and making a musical instrument, or at the very least, making the part yourself. Using machine heads is sort of like cheating to me and sort of kills the spirit of "this something I threw together with crap I found in my garage."
Violins, violas, and most cellos stayed with pegs to keep the authentic look in the style of Stradiveri or in the style of Amanti, and added tailpiece tuner machines instead of headstock machines. some cellos ( https://youtu.be/UzJ9dMYu2AM) and all double-basses have tuning machines because the string tension is just too tight.
I have tried to make 2 handmade worm drive gear tuners, as a experiment.
These tuners are really not an "alternative" to machine heads, because they are indeed real worm drive tuners themselves, but they are handmade, and they are BIG!
Is it possible to make worm drive tuners, using only handtools?
I think so, and I have tried to make worm drive tuners, one smaller, and one bigger, but they are both much bigger than ordinary worm drive tuners (machine heads).
The worm itself is not made by using a lathe and carving away the redunt materials.
Instead an add-on method is used, where a cord is wrapped around a dowel, and some nails keep it in place.
The worm wheel uses nails or wire as »teeths«.
Two kinds of dowels are used.
The thin axis is made of a Ø6 mm thick flower stick. The thick axis is made of a Ø22 mm broom stick.
The worm drive tuners are very big, so they are placed on the instruments body and not on the headstock.
Here is a video: