FWIW, all the PPT I have & have used is/was blank, and the perforators punched the feed hole along with the data. However, I also have some edge-punched cards, which use the same perfs & readers as PPT, and these ARE pre-punched, presumably to avoid long-term drift across cards. However, IIRC, the perforator does not punch the feed hole when it senses a card instead of tape. So, technically no problem either way, although re-punching an existing hole is not usually a good idea. For the curious, EPCs (not to be confused with the tiny 96 col cards which also have binary round holes) are similar to 80 col TAB cards but are continuous, connected with perforations at the ends and stacked accordion-style. They go through the PPT perforator just like PPT, getting punched along the edge, and are subsequently separated and used like other punched cards. Sounds like you're embarking on an ambitious project; I think you'd need some massive solenoids. The way it's usually done is to drive the punch pins with a motor-driven cam and the solenoid interposers only select which pins are driven. I've still got some punches & parts if you're interested; threw some of it out since no one seemed interested (except Steve, who understandably couldn't wait :), and it seemed like more hassle than it was worth, but I think there's still some stuff in the pile that'll be a lot easier to work with than building a perforator from scratch, either complete units or punch blocks/dies. Mind you, if you enjoy that sort of challenge I wish you well! And how about a reader (or two)? mike ------------------------ Date: Fri, 8 Mar 2002 19:36:13 -0600 (CST) From: Bill Richman <bill_r(a)inebraska.com> Subject: Blank Paper Tape Question Does regular paper tape normally come with the sprocket holes pre-punched, or does the device that punches the data holes also punch the sprocket holes? I recently bought some "paper tape" from eBay, and it looks like the right stuff except it's totally without holes. I don't think I've ever seen "virgin" tape before, but I had the idea that the sprocket holes down the middle came with the tape. I'm kicking around trying to build my own tape punch, since I have been unsuccessful at scrounging or buying one so far. I picked up some stainless steel flat and some rod of the appropriate diameter for the holes today, along with some solenoids for actuating said rods. I'm thinking of machining the stainless to make my own punch, but the lack of sprocket holes on the new tape has me confused. Do I need to add another solenoid and pin to punch a smaller hole for the sprocket, or did I just buy some odd-ball tape?