Hmmm , interesting point!
Ok , Ive got the pot replaced with a coupler. As soon as I can, I'm going to remove the coupler and the connecting shafts. Then, I'm going to check where the setscrews tighten into the recesses in the shafts. If there is the kind of movement you are suggesting, I should see witness marks where the setscrew is moving up and down the shaft. Also I'll check the bearing for damage or excessive wear,. If I find evidence of that , I'm removing the works and doing the mods shown by 72bluNblu.
Great comments and suggestions guys!