Hi Thomas
I use shims between the outer gear block and the frame on my G11S.? The general procedure is to push in 2 directions, tangential towards the motor to remove the lateral backlash, and radial towards the crown wheel.? The latter is the tricky part because the crown wheel is never perfectly round and the motors can bind up.? What I do to sense if the radial pressure is too much is to disconnect the stepper and manually turn the worm.? I had to do it so often that I don't use the cover plates anymore. It is best to leave some tolerance so the motor does not bind up elsewhere.? The shims work but not consistently, I suspect that heat expansion may have something to do with it.? Also pay attention to how much you tighten the clutches because it interacts.? The spring loaded worms will probably fix this, otherwise use friction and/or weight imbalance to preload the worm gear.
