Hello Lee,
I don't know if I'm telling grandmother how to suck eggs but a wood that is in the process
of spalting is in the process of rotting!
Depending at what stage it has reached it will become brittle, it will become soft, and eventually
it will just crumble to dust.
So in the early stages which your pen seems to be in it is probably a little brittle, and remembering just how thin
the wood is at the ends of the tube (maybe less than a millimeter) it can flake or crack.
I would suggest when you are getting close to the bushes, repeatedly soak the blank in thin CA, whilst taking very fine shavings
with very sharp tools. The lathe speed is fine.
John. B
BTW,,,nice looking pen. :wink: :wink: :wink: