While surfing the internets, I found this list of drummer jokes that someone has maliciously edited into bass player jokes. These are the worst ones. This is not funny at all. This is the sort of thing that gives guitarists a bad name.
Q: How many bass players does it take to change a light bulb? A: Only one - but the guitarist has to show him first.
This is the angled headstock jig I built from pine scrap, with an already-cut piece of 5" Home Depot maple headstock material attached with clamps. Basically, this jig is a 90-degree square brace, as precise as I could build it. It is square in all three dimensions, the most important being the vertical direction. The final stage of construction of the jig was to smooth all the surfaces on the sander, true up the saw, and then true-up the jig face by shaving it with the saw. You can see that the angle of the headstock is easily selected on the saw. The accuracy of this angle is not critical, as long as you are in the ballpark, anything will work.