My CGEM with the RA axis locked in place while I manually spin the DEC axis. The counterweight shaft wobbles because of the locking nut, without the locking nut the wobble disappears. Heres a link to a video of the shaft only and no wobble. https://www.youtube.com/watch?v=8qnR5aSt56o&list=UUBI0oopIg4-zmKRtW0s9r4Q&feature=c4-overview
https://demonstrations.wolfram.com/WaveSpringWasher/
The Wolfram Demonstrations Project contains thousands of free interactive visualizations, with new entries added daily.
One way to secure a bolt and nut joint is to put a wave spring washer under the nut. The nut compresses the washer, whose spring force increases the friction between the threads of the nut and the bolt, reducing the chance of a loose joint.
Contributed by: Sandor Kabai