Originally Posted by adjangs
Easy mod to get better precision:
The highlighted collar is meant to be situated so that the screw lines up with a hole in the shaft... but the hole is drilled too high and allows the shaft to move up and down when the servos push up and down on the swashplate. I've found it's enough to snug the screw up against the shaft at a lower position even though there is no hole there.
My V911 has almost no axial play in the main shaft. If I pull up and down on the main shaft in the axial direction, I can feel just a hair (maybe 0.003") of freeplay.