Jerome tuning machines are among the rarest of those used on very early Martin guitars, going back to the 1840s-50s. They were the finest made at the time, from France, and are rarely if ever seen available separate from guitars today. Offered here are one complete bass-side, in the “gear-over” configuration with 68mm spacing, 100% complete and working well, with a tiny bit of wiggle in the near-side stanchions that can be tightened by a skilled craftsperson. Also included are about half of the backplate from the other side, with clear evidence of reptile dentistry having been performed by parties unknown in centuries gone by. One extra original bone button and most of one worm shaft are also included. $500