I saw Matt's comment about repairing music roll dies on MMD this
morning.  He mentioned that Eddie Freyer used a donut-shaped punch to
strike around the hole and thus force some metal toward the hole.  I'm
surprised that this would work with a hardened die.  Using a hardened
punch to address a hardened die would probably result in a broken
punch.  Eddie Freyer probably had to soften the die first, then use the
punch, then ream the hole, and then harden it again.  And you couldn't
really do this with a die that had a row of holes, because there is
little or no material between the holes.

It seems to me that it would be easier to use a surface grinder and
skim off a couple thousandths from the top of the die and then shim it
up to make it flush with the surface.

However, I'm writing to mention something that came to mind when I was
reading Matt's post.  Clockmakers sometimes do this when the pivot hole
in the plates of a clock are out of round.  They use a round-nosed
punch and they strike all around the hole (actually called a pivot hole
or bushing) to cause a little brass to move toward the hole so as to
urge the hole back into shape.  Then they ream it round again.

It's sort of messy and doesn't look nice, but it does avoid the trouble
of addressing the proper solution, which is to drill it out and install
a new bushing.  The technique is called "beating around the bush,"
which is where that saying came from.

Craig Smith