"Bob Engelhardt" wrote in message
...
Rob Kramer wrote:
...
My question: how can I best re-harden them? ...

Do you really want them hard? Why? Bob

Jaws for holding finished pieces are best if they're hardened. While I've
not done a hardness check of mine (a Kurt), I would assume they run in the
mid 50Rc range. That avoids dinging the jaws with chips or other objects,
and transferring the dings to the next part installed. Hardening the jaws
is a good idea.

Harold