My simple collet pusher has been working OK, but the locking pin was a few mils too small for the hole in the spindle and eventually put a burr on the edge. The fix is straightforward, although I’ve been putting it off for far too long; I warned you about this in the original post.
Shoemaker’s child, anyone?
The locking hole in the spindle starts life at 0.094 inch. I grabbed a #40 drill in a pin vise and drilled it out to 0.098 by hand, which wasn’t nearly as difficult as you’d think, took out all the deformed metal, and didn’t even leave any burrs. Ditto for the hole in the collet pusher.
My heap yielded a defunct #40 drill, from which I cut 15 mm of shank with a Dremel abrasive wheel. Chucked the shank stub in the drill press, spun it up, and applied a Dremel grindstone to put a very short taper and a nice smooth end on it.
Pulled the old pin from the handle I built a while ago, added a dot of urethane glue to the new pin, and squished them together (tapered end out!) in a vise until cured. Done!
No, that’s not a burr on the hole in the pusher…