In the Ridgewing self-tuning headstock, the string tensioning lever is a side-action. All of the strings’ tension is transferred to the guitar body via the lever’s axle and a single contact point on the face of the lever where it is transferred to the hard steel push-rod running down the center of the headstock to the end face of the neck shaft. Because these contact points are so small, the pressure at the contact points is tremendously magnified up into the range of the yield strength of common metals >20,000 psi.

Originally the lever was molded from carbon-fiber, but being mostly epoxy, when the strings were put up to tension, it simply screamed and died. Next we tried making the lever out of aluminum, but its contact face spalled and crumbled almost immediately, no matter how well lubricated. The obvious next step was to make the lever out of hard steel, with its contact surface mirror polished to meet the similarly polished push-rod. However, a steel lever would be too heavy for the headstock, which was already too heavy with the Tronical self-tuning mechanism. An ideal lever had to have minimum weight and a seriously hard contact surface that could be lubricated. What to do? Get fancy!

A compound lever made of carbon fiber containing a small hard metal insert seemed worth a try. The carbon-fiber would keep the weight down, and a metal insert would provide a hard-enough bearing surface just where it was needed. As a bonus, a hybrid lever could be made using the existing carbon-fiber lever mold. The metal selected for the insert piece was Oilite, which is a hard sintered bronze impregnated with lubricating oil commonly used in self-lubricating bearings.  So we knew it was tough stuff.

A piece of Oilite was procured from McMaster-Carr, and was then hacksawed and hand filed until it fit the drawing, which didn’t take too long. The curved outer contact surface was smoothed and polished to a mirror finish.

The trapezoid-shaped “blade” on the insert piece was what ends up being embedded in the carbon-fiber lever. Its rough appearance was intentional scoring of the surface for better adhesion when molded into the lever’s carbon-fiber-epoxy matrix.

Opening the mold is always fun, particularly when something new is being tried. Here the new lever hasn’t even been taken out yet, the surfaces still shiny with mold release, like a new baby.

Cleaned up, the new lever was ready for action.

The compound lever worked but it was a pain to make. Precision hand-filing an odd-shaped piece of hard metal the size of a cashew can tend to leave fingertips and tempers raw.

A most beautiful and elegant lever solution was designed and fabricated by CNC out of titanium by Ridgewing’s wizard engineer/guitarmaker friend/Maker Bill Daly. It wasn’t quite as light as the hybrid lever, but it made up for it with pure class.