Dean et Al,
Plastic servo arms with ball joints are not a good idea. The ball joint puts a tangential load on the servo arm since it's mounted on top of the arm. This causes it to twist and eventually break. Either use a metal arm or a wheel. Clevis' transfer the control surface load force directly in line with the servo arm but a ball-joint does not. There - you were warned. LOL

cmoore806: You don't want the servo to fit snug in the hole. This will transfer vibration to the servo, even if you're running an electric motor. This should be avoided. That's why servos have rubber grommets. Allow them to work. Just line the hole with 1/16" balsa (orientate the grain vertically) and mount the servo with lite ply or hardwood rails. If you really want to make it bulletproof and neat, make a lite-ply rectangular servo "tray" that fits snugly into the servo cutout while maintaining at least 1/32" clearance to the servo on all 4 sides. Glue this into the servo cutout. Done.

John Pavlick
Team Black Magic, Tech-Aero Designs