I hear you Bill. I've had the same experiences with dial scales, lenses, plastic
parts, etc. Luckily, I tend not to make the (exact) same mistake twice, or at least a
third time. The worst "Oh Noooo" was last summer. I had to pull a Ford Supercab pickup
truck into my garage at a sharp angle through the narrow doorway. Not knowing if the
fold away mirrors had ever been moved, I grabbed a can of PB Blaster and lubed the
pivots and folded them back neatly out of harms way. I went into the house for lunch.
  When I returned both mirrors were laying on the floor, separated from their mounting
bases. In a matter of about 37 nano-seconds my insides turned to jello and I knew
exactly what had happened. The Blaster softened and crazed the plastic housings and
the spring tension popped them off as pretty as you please. That was a $300 brain
cramp. Another mark in the Don't Do This Again column.

  Good luck with your dial glass Julian.
                        Tom