Reply by crank49

I suspect the ones that quit advancing before the spur broke through just stripped the threads out in the wood surrounding the spur. If so, you should be able to advance the bit with enough pressure.

In the case where the spur broke through, just add a backer board for the spur to bit into.

-- Michael :-{| “If you tell a big enough lie and tell it frequently enough, it will be believed.” ― A H