This is the business end of a standard Ridgewing headstock.  From the bottom up are the molded headstock body, mounting pins, lever with built-in lever axle, headstock veneer, string “mount”, and string-guide “cap”. The whole stack  is screwed together by the two flat head machine screws visible on either end of the cap.

The cap and mount are 3D printed, and the cap is a dandy place to put a serial # or other scrimshaw. The mount has two functions.  One is to lift the strings clear of the lever action, and the other is to clamp the lever axle in place. This little experiment revealed that the lever axle applied an upward force that the two flat head machine screws couldn’t handle, allowing the mount to buckle upward at the center.  This was cured by adding a couple more machine screws hidden below the cap that threaded into a pair of brass inserts installed flush on the back of the headstock, for a total of four screws. Serious screw medicine in a small space, and it worked. The lever axle has to both be held firmly in place but also allow the lever to rotate freely. These two mounting pins here are super light-weight carbon fiber pultrusions, and were molded right in when the headstock was molded.  

There is a lot going on here mechanically in a small space, and the torque is considerable. The mounting pins slip-fit into 6.35mm (1/4”) diameter brass-lined holes in the end of the neck that are precisely 26.67mm (1.050”) apart, center-to-center (the most secret Ridgewing dimension). The brass-tube lined holes that receive the pins get VERY close to the fingerboard surface. This drill guide is used for putting in these holes, which are angled 15 degrees from the fingerboard’s bottom plane:

A simple table-top clamping jig holds the neck for drilling slightly sloppy oversized holes with a hand drill. The final brass-lined holes are precisely positioned in the oversize holes by mounting the pair of brass tubes on the dowels of this hole guide jig, with a little bit of plumbers tape covering the ends of the brass tubes.

Our good friend 5-minute epoxy is gooped into the oversized drilled holes, and the jig with the brass tubes is pushed home. A couple of little vent holes were drilled down into the end of the drilled holes from the fingerboard to allow the excess epoxy to squeeze out. When the epoxy sets, pulling out the pins leaves the brass tubes behind, just right.

Note that the exact position and angle of the two mounting holes doesn’t matter as long as they are precisely parallel and 26.67mm (1.050”) apart, which this little jig takes care of. This is an expression of the Ridgewing design philosophy that, wherever extreme precision is required for critical features on instrument components to allow instant interchangeability, the necessary precision can be implemented with simple jigs and hand tools on a kitchen table. Anybody can do it.  Dream up some cool new Ridgewing guitar component, saw-saw-file-file-drill-drill-screw-screw-goop-epoxy-paper-towel-paper-towel, and, magically, your new component fits perfectly into the guitar. Flip the headstock lever, and you are playing it in seconds. Whoa!? Is your new dream part great? Put the prototype in the Ridgewing store for sale, and maybe you can change guitar history. Ridgewing is the guitar for free thinkers. Major guitar manufacturers - who needs them anymore?