[GreenKeys] paper slitter technology

[dmm at lemur.com]

In a recent thread, Pete Lancashire mentioned a paper slitter for
cutting down rolls (for printing paper? for punch tape? for both?)
Having never seen such a device, I'm wondering how it works.

Does it unroll the paper past a knife (knives?)  and then re-roll it on 
take-up reels?  Or does it cut into a roll all-at-once as, say, the roll 
spins on a lathe?  Or does it use some other method?

I recall that the accounts of Morse and Vail indicate
that they had to build a "lathe" for cutting the paper tape for their
registers, but that was a long, long time ago.

Could one start with, say, a 1" wide roll of paper and cut it down
on a lathe to width?  (I'm thinking here of 7/8" tape for 6-level TTS.
You can still get the 1" new, but 7/8" is harder to find.)
Or is this just asking for the roll to come unwound at speed,
turning the shop into an elaborate paper spider's web?

Just curious.  One would think that it would be possible to
"homebrew" a slitter that would suffice for the small quantities
needed for amateur use.

Regards,
David M.
===
Dr. David M. MacMillan * dmm at lemur.com * www.lemur.com & www.CircuitousRoot.com

   The first rule of intelligent tinkering is to save all the parts.
       - Paul Ehrlich (1854-1915); Aldo Leopold