What do you use for drilling the hole for the bridge ground in a JB? Do you drill from the bridge to the pup cavities or directly to the control cavity? In this case which bit do you use? It's a very long hole...
Do you have tricks for a perfect work?
Stefano, I use a 1/8" bit that is 12 inches long. I've never measured the angle, but you should be able to see where the exit hole will be in the control cavity. The first thing that goes wrong is the bit skips across the top of the body because of the shallow angle. Fender addressed this by drilling a small, flat bottomed hole (1/4 to 3/8 inch) under the bridge. This will give the bit a "corner" to bite into.
Perhaps a less stressful way to install a ground would be to run a piece of brass shim stock from under the bridge, across the top into the pickup cavity. You can solder this to the ground plate under the pick up (if you have one) or solder a wire to it and run this into the control cavity. Fender did this on the earliest Jazz Basses. Attched is a picture.
I use a 6mm drill bit, 25cm long, bought at a local hardware store. I start drill perpendicular to the top (in the bridge area) for maybe 2 or 3mm, than gradually angle the drill bit to the good "estimated angle". I recommend some practice on scrap wood, but it's a quick learned skill !