Since I had planned to tighten the tuning machines on my new Fender MIM standard jazz bass, I thought I might as well take a few pictures and post a little tutorial:
If the tuning machines on your MIM bass feel loose and unprecise, the following tip will tighten them:
First remove the strings from the headstock:
A look at the back of the headstock.
Get out your screwdriver and unscrew the large philips screw on top of the gear, and you'll be able to disassemble it:
Let the tuning post drop away. Underneath the wheel you'll find two washers, a black plastic washer and a metal one. Their job is to make sure the gear's wheel and worm fit tightly together:
Here they are, removed from the whorm-wheel:
The metal washer has a slight bend to it. The more it is bent, the tighter the gear of the tuning machine will work. Now carefully bent the metal washer, so it is slightly concave:
Now you just need to re-assemble the whole enchilada, and voila, your tuning machine will be nice and tight!
If it is too tight now, you simply have to unbend the metal washer a bit.
Remember this tip is for Mexican Standards only. AFAIK
, the other Fender basses use another system.