Hi,  Last year a friend and myself purchased a book punching machine
from Holland just for our personal use.  Although it had a new set of
punches for keyed music, it unfortunately did not have a circular punch
and die for keyless music and my organ is a Wilhelm Bruder Söhne Model
77 which has holes at 3.5 mm centres and I have been advised the punch
needs to be 3.2 mm.

A local general engineer who has done work on a number of instruments
I have restored has agreed to make the punch and die but he has asked
me to find out what would be the best specification for the material
he should use.  Obviously we would like to get the punch made to the
highest standard.

Being a circular punch for keyless music the punch, even though it
is a foot operated machines, will be required to produce thousands of
holes in card in each reasonably sized book and it needs to be hard so
it does not constantly need sharpening!

Any advice or help would be appreciated.

Jonathan Holmes
Pendeen, Penzance, UK