Today I made a wrench featuring a bar of aluminum with two steel pins at the spacing needed to address the holes in the quill bottom plate. Eventually I got the bottom plate out and was able to find what has happened with the spindle pin that prevents the collets from rotating within the spindle when the reaction torques get high. The pin is actually a hex screw with a bump on the end against which the collet key way slides. The screw was in two pieces and the “bump” was well worn down.
Not having the replacement yet I put the bottom quill plate back on, but the hex retaining screw for it wouldn’t go in far enough to allow the quill to go all up so that the draw bar would work. So that screw is out also, but the bottom plate appears to be well stuck on as trying to remove it for the purpose of adjusting it’s final position so that the retaining screw could find the divot, recess into the quill side and allow its full travel. Instead the wrench tool broke off one of the steel pins.
Bottom line is that the current arrangement doesn’t seem to permit collect slippage unless the torque requirements are really high, such as I saw with the use of a slitting saw last week. So no further loss of functionality.
I may research the part number for the spindle pin this week and make a mightier quill wrench.