Now this is a cool vintage tool. They don’t make ’em like this any more.
Occasionally, customers want a truss rod installed. We recently installed a low profile (Stewmac 1260) in a National Brand guitar neck.
Showing below is a Marples Drill bit guide. This is the only guide I know of that can span a guitar body. Adjustability allows all kinds of drill bit locations and settings. Here we are drilling the hole through the upper bout top cross brace. This hole allows access to the truss rod nut by an allen wrench. The shaft sticking out to the right is an extra long 1/4 inch drill bit.
This shows all the parts that come with the kit. Pretty cool I think.
©2018 D.R. Hanna