I have been told this before; in fact, it was one of tips that Nick provided during a Sawdust Session. But having been told doesn't mean it is done, or done right.JPG40504 wrote:If the 'lock' is installed properly this always happens. To make it 'proper' take them completely off the SS. Screw both screws all the way into the 'handle'(one is RH screw, the other is LH screw). Barely rotate the screws so they are in position to slide back onto the SS. Slide it back onto the ss 'grooves' and tighten. This will ensure the both screws protrude the same amount when adjusted.
Just for grins and giggles, I went to the shop this morning and checked my locks on the extension tables.

Adjusting them as JPG has just suggested here cured that problem. They are now much more stable.
As a follow up, I installed the tailstock and locked it into place. It is NOT absolutely rock solid but I don't believe it is loose enough to cause problems during turning.