I sometimes use a box knife...starting in and working out...usually able to fix threads until the last one on the very outside of the hub. It is always difficult to salvage the STARTING thread. That's the critical one.

It would be cool if you could find or make a tool that is a snap ring consisting of inner threads that are the correct pitch for chasing outwards. I bet someone already has one - much like the inner snap-in thread chaser for crank arms.

=8-)