ORIGINAL: Gray Beard
I get my screws from Micro Fastener, hex head screws. I pre-drill the holes under size, thread the screws in then back out. Add a drop or two of thin CA then let it set up. Now install the servos and tighten them down good.
Gray Beard's got the goods! I do exactly what he does then I add a drop to each screw and drive them home, never had one come out yet (knock on balsa...) Every once in a while the rubber grommet gets glued too, but small price to pay to make sure your servos stay on the job. Metal to metal ALWAYS needs thread locker of some sort, if at all possible, run with nylon lined nuts (but not both), they are Gump proof!