Harald,  About two years ago I built a computer controlled punch in
order to produce punched rolls for Raffin 20- and 31-note organs.  It
also produces a 26-note version of the Raffin scale, and any other
scale you like, even 88-note piano music!

The computer software is designed to read standard MIDI files.  The
mechanics are quite simple and there is a relatively simple electronics
board to assemble.  It uses stepper-motors and the results are highly
accurate.

I wrote a small book which I sell, complete with a copy of the software,
for the equivalent of US$ 68.  The software is fully professional in
its concept.  It reads the MIDI file and converts to stepper motor and
punch commands via the printer port.

There is a user program in which you can enter all the parameters of
the roll you wish to punch: note scale, hole spacing, hole position,
motor stepping rates etc.

If you would like to know more, please mail me back and I will give
details and answer any questions.  My book is written specially for the
hobbyist and is selling well all over the world.

Bob Essex
Warwickshire, England