I already responded off-list to Harald Mueller's query about
perforators.  This is what I wrote him:

 - - -

I hope I understood your question to the 9-29-00 MMD.

If you get to California, go to Turlock, a 2-hour drive southeast
of San Francisco, and watch Jeanne Malone (Play-Rite Music Rolls, Inc.)
perforate music rolls using both newly-made machines and an old Acme
perforator, which was the work-horse of the old-time perforating shops.

A piano roll perforator can punch out as many as 18 or so copies at
a time.  The force needed to punch through that many layers of paper
is provided by mechanical force in the form of a ram which rises and
lowers (by less than 1 cm) over the 100 punch pins to force them into
the paper.  Neither vacuum or air pressure would be sufficient to do
the job.

In the old days, the perforator was controlled by a paper or cardboard
master "roll" into which the tune to be copies was punched.   The master
was made on an enlarged scale, in Wurlitzer's case a 3-to-1 scale, in
which the perforations in the master were three times as long as they
were to be in the finished rolls.  This is necessary to minimize
reading and copying errors.

There are a couple of sites where you can see perforator views.  One
of the original Wurlitzer perforators is now in the Herschell Carrousel
Factory Museum in North Tonawanda, N.Y., where it is being used once
again to cut band organ rolls using original Wurlitzer cardboard
masters.  See the pictures at: http://www.carousels.com/hmusem2.htm

Two modern 88-note piano roll perforators are shown in the MMD
Archives.  The one built by Dick Tonnesen [Custom Music Rolls] has
good explanations about its operation, so it is worth studying to see
how the punch ram on the old perforators worked, which was on the
same principle used by Dick.  Apparently his machine punches out only
5 or 6 copies at a time.  His pictures are at:
http://mmd.foxtail.com/Pictures/tonnesen.html

The other modern one is David Saul's [Precision Music Rolls] at:
http://mmd.foxtail.com/Pictures/saul.htm    But his pictures are
harder to understand.

The QRS company in Buffalo, N.Y., still uses the old equipment designed
by Ernest Clark in the early part of the century to produced piano
rolls.  The QRS perforators produced well over 30 copies at a time,
because each assembly is really two perforators, side by side, driven
by one master reader located between them.  There are pictures ( but
they aren't very clear) at:
http://mmd.foxtail.com/Pictures/qrs1975.html

I hope this helps you understand some of the technology.

 - - -

Yesterday I went over to North Tonawanda and took about 40 pictures of
Wurlitzer perforator no. 12 in the Herschell Carrousel Factory Museum.
I will send a couple to the MMD editors for inclusion in the Archives,
but the bulk of them will be used to illustrate a description of their
operation and their unique features which I am going to write this week
for my online 165 roll catalog.

One of the unique features I am claiming for the Wurlitzer perforators
is that they used pre-trimmed paper.  I know Dave Saul's, Richard
Tonnesen's,  Play-Rite's, and QRS's perforators all trim as they punch.
Was Wurlitzer's the only design that required trimming the paper to
exact size before running it through the perforator?  Please correct
my belief, if I am wrong, before I put it in writing.

Matthew Caulfield

 [ See Matthew's Wurlitzer site at http://wurlitzer-rolls.com/
 [ -- Robbie