The sticky key issue is alive and well. After a couple hours of rotating through cycles of drilling and trying the key, I lost patience and switched to a dynamic duo of metal-hungry bits for the drill and the dremel. Thirty seconds later, there is a smoking crater reaching to the far side of the shaft with the diameter of a dime.

Still unable to turn the key, I re-read the instructions and noticed the sage advice on the last page: "How do you know when you've removed enough material from the pin? When you can slide the assembly left and right past the locking hole, you're done."

Suffice it to say I think I've screwed this up by not reading ALL the instructions prior to attacking. So, I'm going to carve this assembly into pieces if I have to in order to get it out. Hope I can still retrieve the tumbler!

Merry Christmas to all! And thanks for imparting lessons learned.