Just a photo I made when installing a set of mechanical pegs from pegheds.com
The installation instructions say that we should drill a 7mm hole and ream the hole to a size so that the pegs are a few milimeters from going all the way through to their final position.
We are then supposed to "cut" a thread in the headstocks wood by turning in the peg and using the threaded shaft of the peg to do the cutting. We shall turn the shaft of the peg and never turn the head of the peg.
This turning and cutting the thread can be hard for our fingers, so it helps to turn a rubberband around the shaft. As simple as that. My fingers not as good as they were and these little tips help a lot.
I didn´t find out this by myself, but because I recently installed a set of "pegheds" on a fiddle and the instructions for the pegs said to do use a rubberband. Violin pegs are smaller, meaning that its more difficult to get a good grip on the peg shaft and besides that, you have to cut the thread in maple which is a lot harder than the Spanish cedar used on flamenco guitars.
The guitar is number 109.