I'm going to go with a dull bit. Not the spur that
severs the grain at the outside of the hole, but the
edge that peels off the wood for the hole. If dull
it would tear out chunks instead. Chunks can
clog things up whereas shavings won't.

If necessary file the edge then refine with
slip stones. The sharper that edge the easier
the drilling. The easier the drilling, the
easier it is for the chisel to do its job.

As for the Forty Cent Method for setting the
bit to chisel spacing - thank the Fisch rep.
I just did the illustration and put it up on
my site. That said - you're welcome. Pass
it on when you can.

charlie b