They really are small and there are 5 of them for $3.80 - quite a deal.
So I picked out one with the silk screening right down the middle and set to work.
First I laid small towels over the kitchen table and pulled out the preamp/tuner.
I covered the are with masking tape to protect the finish. The body of the bass is tapered, so there isn't a right angle from the top or bottom you can use. So I used the preamp holes as a guide. The side holes are 1 1/2" apart so the center line was an easy 3/4". The switch is close to 1/2" tall and 5/16" wide. I marked this out on the masking tape carefully - making sure it looked even and parallel to the preamp holes.
I used my dremel to drill the corner holes( not the best job, but they just need to be inside the lines.
I then switched blades for a carving tool. This worked like an itty bitty router. It quickly cut out a rough hole.
I carefully squared up the sides and corners with the router bit and then switching to a triangular file. After a few and test fits the switch just slid in.
Next I set the bass on its side and ran the wires I added earlier out my new rectangular hole. I soldered those on the switch and reinstalled the preamp.
Next was to reassemble everything, cleanup the sawdust and test it out.
