In answer to Gary Goldsmith's inquiry, that perforator is definitely
a converted Autotypist perforating system.  Back in the 1980s I picked
up a couple of these (for $5 each) at the Purdue University salvage
sale with the same intention of converting them to cut music rolls.

I needed two because the original standard typewriter keyboard setup
was for 50-something holes, punching at 5 holes per inch.  I had a
machinist make up dies, guides, and some other pieces add the punches,
keys and linkages, from the other for 65-note 6 holes per inch spacing.

Brian Thornton - Short Mountain Music Works