Back in the HP 2000 days we used to blow holes in miles of Mylar tape with BURPE teletype brand punchers and also a large TALLY punch... even if you find one of either missing the electronics the punch mech and pins are HARD and will cut though anything! if you find one with real good electronics they are usually a parallel type of interface...
my experience with Facit stuff it wore out easily compared to those other two units. Although The Facit units were used as were the others we liked so we had no real history on previous use so just my 2 cents worth based on personal experience in th e days of old. Ed# SMECC In a message dated 5/1/2020 12:17:22 AM US Mountain Standard Time, cctalk@classiccmp.org writes: On Fri, May 1, 2020 at 5:02 AM Anders Nelson via cctalk <cctalk@classiccmp.org> wrote: > > Hi all, > > I've had a paper tape reader for a while but never had a punch to make new > tapes, and the ones i've found are not only very large but also very > expensive. So I'm toying with the idea of making an open-source punch, but > I can't find any detailed diagrams of how the mechanism works. > > I'm assuming (without any data to back it up) that there is a cam, an array > of spring-levered pins, and horizontal spacers controlled by solenoids that > bridge the gap between the cam and each punch pin when called for. > > Does anyone have insight into how reliable/fast paper tape punches work? There are 2 basic designs.... The mechanically simpler one has a solenoid that directly operates each punch pin. The well-known Facit 4070 is of this design, using rotary solenoids and drive levers (I am sure the service manual and parts list (which contains the exploded diagrams) are on-line. Another example of this type is the Heathkit H10 which uses normal linear solenoids. More common is to have a motor driven crankshaft moving a little frame up and down. This goes over the ends of the punch pins and has a bracket to pull them down at the end of the punch cycle. Solenodis (quite small solenoids, almost like relay coils) move spring metal strips (normally called 'interposers' in the manual) into said frame under the punch pin so that the pin is then forced up and through the tape as the frame rises. The Teletype BRPE, GNT34, many Data Dynamics punchs, etc are of this design (to name the ones I can see without getting up). Be warned that making any paper tape punch is going to be non-trivial. Grinding and hardening the punch pins and making the die block for them to run in is quite a difficult machining task. And that's needed what ever drives them. -tony
