Re: DIY Paper Tape Punch - Mechanism diagram?
Anders said > 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? The idea behind the paper tape punch is that the solenoids themselves don't supply the force to do the actual punching, they instead set up the punch pins which are then driven by a cam by a motor with a lot of grunt. I suppose it's like the mechanical equivalent of a transistor switching on by applying a small base current. The once-popular Roytron punch mechanism is described in http://www.bitsavers.org/pdf/roytron/Roytron500_1966.pdf and may be what you are looking for. It's somewhat comparable to how the keyboard mechanism operates in a Selectric typewriter where interposers drop into place and the cam profile on the filter shaft drives them forward. Or a Creed teleprinter keyboard with toothed code bars that suspend lateral bars being moved with mechanical force. I've also thought about a home made punch that might be built using the Teletype punch blocks that have been on eBay, augmented with a bit of machining, motor and some 3D-printed parts such as the frame. But that's still just a bunch of ideas at present. As for making tape by means other than a punch, if you have a home vinyl/stencil cutting machine you can make working paper tapes using my ptaf2dxf utility https://github.com/1944GPW/ptap2dxf It's very slow compared to a real punch and on the standard 12" x 12" cutting mat these machines are supplied with, there will be a number of short tape segments cut that then need to be glued together. But, as a novelty, it works :) Steve.
Re: In search of Three Rivers PERQ 1 Keyboard
On Fri, May 1, 2020 at 2:18 AM Al Kossow via cctalk wrote: > > On 4/30/20 2:55 PM, Josh Dersch wrote: > > > It is, I refoamed mine for VCFPNW last year. I can take internal pictures > > if it'd help anyone out. > > > > - Josh > > > > can you dump the firmware? or was that already done for the PERQ emulator? > it should be some flavor of 8048 The PERQ 1 keyboard uses a semi-custom encoder IC labelled AY-3-4592. I suspect there is a mask ROM inside that gives the key mapping and that it was used in other keyboards as there's a PROM (74S477) between the outputs of that encoder and the PERQ. I have a dump of that PROM, it's in the archive of PROMs/PALs that I sent to somebody yesterday. The PERQ 2 keyboard is a standard-ish Keytronics thing with a serial output. That does have a ROMless microcontoller (8035?) in it, again I've dumped the firmware ROM. -tony > >
Re: DIY Paper Tape Punch - Mechanism diagram?
On Fri, May 1, 2020 at 5:02 AM Anders Nelson via cctalk 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
Re: DIY Paper Tape Punch - Mechanism diagram?
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 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
Re: DIY Paper Tape Punch - Mechanism diagram?
An option is to use a computer controlled cutter like Cricut or Silhouette to punch a tape. Github has software, look at PTAP2DXF. It has a example pix of a tape made with a "2016 model Silhouette CAMEO vinyl/stencil cutter and a used large yellow business envelope". Interestingly, the tape is labeled "dec-11-lp2c-po", so it was a copy of something DEC. Link: https://github.com/1944GPW/ptap2dxf Another avenue is old CNC machines. They used paper readers and some had punches. Spare parts are available but they are pricey. Wayne On May 1, 2020, at 12:17 AM, Tony Duell via cctalk mailto:cctalk@classiccmp.org>> wrote: On Fri, May 1, 2020 at 5:02 AM Anders Nelson via cctalk mailto: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
Re: DIY Paper Tape Punch - Mechanism diagram?
I've cut Mylar tape with a Glowforge laser. It cuts very nicely but the alignment is a major hassle, plus you can only cut ~15" of tape which doesn't go very far. Not worth the effort. If you were to build a custom linear drive it might work. But also very slow. Here's a picture of a mechanical (Teletype 33) punch block. These are quite high-precision parts with hardened pins. The pins drive through a narrow gape for tape, into matching holes in the top of the block. On the Teletype, the drive mechanism is slow, and the punch sits quite a long way from the single solenoid that sets up the bits. I assume high-speed punches have a similar block but a more direct (parallel) actuator. https://photos.app.goo.gl/F6QZQE3tiKgiGB6c7 CuriousMarc has a good video showing this sort of punch in operation, https://www.youtube.com/watch?v=yzulZaJbdUU&list=PL-_93BVApb5-84G5kmgfuu7TQduTMc73H&index=8 On Fri, May 1, 2020 at 12:02 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? > -- > Anders Nelson > > +1 (517) 775-6129 > > www.erogear.com >
Re: DIY Paper Tape Punch - Mechanism diagram?
> On May 1, 2020, at 3:17 AM, Tony Duell via cctalk > wrote: > > On Fri, May 1, 2020 at 5:02 AM Anders Nelson via cctalk > 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). A variation of the second version uses a lifting mechanism for the pins that has a "knee joint" in it. In the resting position that joint is slightly bent so the cam force merely bends it further, the way your leg does when you knee is flexed. The solenoid pushes the joint sideways, locking it, like a locked knee, and now the cam will drive the punch pin 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. True. At least the pins may be something you can buy: pin gauges are made to extreme precision in 0.001 inch increments and may well work. Or metal dowel pins, if they come that small. But that still leaves the die block. Would drilling and reaming be good enough? paul
Re: DIY Paper Tape Punch - Mechanism diagram?
At 07:18 AM 5/1/2020, Hugh Pyle via cctalk wrote: >I've cut Mylar tape with a Glowforge laser. It cuts very nicely but the >alignment is a major hassle, plus you can only cut ~15" of tape which >doesn't go very far. Not worth the effort. If you were to build a custom >linear drive it might work. But also very slow. Hmm. You could have N fixed lasers at the spots of potential holes, and then a mechanism to move the whole assembly of them in the shape of a single hole, drawing them all at once. You could have one laser on that moved precisely along the hole row, and use the same sort of mechanical motion to draw a hole. How much laser do you need to cut paper, how much to cut mylar? Were there any paper tape devices that did not use the sprocket holes to move the tape? - John
Re: DIY Paper Tape Punch - Mechanism diagram?
On Fri, May 1, 2020 at 4:32 PM John Foust via cctalk wrote: > Were there any paper tape devices that did not use the sprocket holes > to move the tape? Yes, both punches and readers. The Facit 4070 (and the N4000) punch uses a capstan and pinch roller to move the tape. It's driven by a stepper motor. Of course it punches the sprocket holes. As I said the other day several high-quality optical tape readers (Trend, HP2748) feed the tape with a capstan and pinch roller. They do take a timing signal from the sprocket holes of course. -tony > > - John >
Re: DIY Paper Tape Punch - Mechanism diagram?
> > > 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. > > True. At least the pins may be something you can buy: pin gauges are made to > extreme precision in 0.001 inch increments and may well work. Or metal dowel > pins, if I seem to remember that in some cases the pins are not flat on the business end. And of course they have to be hardened, but gauges are likely to be. they come that small. But that still leaves the die block. Would drilling and reaming be good enough? Probably. The pins need to work smoothly, but with no excessive gaps or they won't punch cleanly. Remember the die has to be made in 2 parts accurately aligned to leave a slot for the paper tape to run in. And of course (the relatively easy part) you need 9 holes in a straight line at 0.1" centres. You then need to harden the die without distorting it. It's not impossible (after all these things _were_ made once). But it's not the sort of thing you can do with just hand tools I think. -tony
Re: DIY Paper Tape Punch - Mechanism diagram?
Wow, what a response! Really appreciate the docs and first-hand experience, this is super helpful. I'm also floored by the complexity of that Roytron punch! Looks like it contains around one hundred separate parts. I'm convinced the punch parts will have to be precision metal so while that's not quite "DIY" it might still be a reasonable bit to CNC, mill or water-jet cut. It also looks like that punch has an escapement mechanism of some sort? Seems like a simple way to keep regular spacing, but if course more parts to buy from McMaster Carr or whatever. Question: did all tapes have indexing holes separate from the drive sprocket holes? Also is there a source for tape with sprocket holes anymore? I also like the idea of using a LASER cutter and a rotating platform like they use to engrave drinking glasses. Add a light vacuum nozzle under the tape past the cutting surface to suck up the chads, and perhaps make the cutting surface wheel with of rows of thin plates as the cutting surface, similar to the thin honeycomb cutting beds of typical LASER cutters. I imagine it'd take an awfully long time to use a traditional core XY cutter versus a galvo-mirror cutter. I have some experience cutting planar items in LASER cutters but little experience beyond basic principles regarding machining/modeling/rotating LASER stuff. On Fri, May 1, 2020, 11:32 AM John Foust via cctalk wrote: > At 07:18 AM 5/1/2020, Hugh Pyle via cctalk wrote: > >I've cut Mylar tape with a Glowforge laser. It cuts very nicely but the > >alignment is a major hassle, plus you can only cut ~15" of tape which > >doesn't go very far. Not worth the effort. If you were to build a custom > >linear drive it might work. But also very slow. > > Hmm. You could have N fixed lasers at the spots of potential holes, > and then a mechanism to move the whole assembly of them in the shape of a > single hole, drawing them all at once. > > You could have one laser on that moved precisely along the hole row, > and use the same sort of mechanical motion to draw a hole. > > How much laser do you need to cut paper, how much to cut mylar? > > Were there any paper tape devices that did not use the sprocket holes > to move the tape? > > - John > >
Re: DIY Paper Tape Punch - Mechanism diagram?
On Fri, May 1, 2020 at 4:48 PM Anders Nelson via cctalk wrote: > > Wow, what a response! Really appreciate the docs and first-hand experience, > this is super helpful. I feel very greedy now. Looking arounds I have (not all working, but all could be got to work, it's things like drive belts I need to get ) 3 Facit 4070s and an N4000 A DEC PC04 Two Data Dynamics units (1130 and 1183) which are 8-level punches 3 Teletype BRPEs A Trend Paper Tape Station (GNT 34 punch and Trend HSR500 reader in a rack chassis) A couple of Teletype Model 33 ASR's A Friden Flexowriter with punch/reader The punch from a Flexowriter on a rack chassis with its own motor. I think there's a couple of bare-chassis solenoid-operated punches here too but I would have to hunt for them. And that's the 8 level ones. For 5 level (only) I have a Creed 444 teleprinter and a Booth-Willmott Model 44 Keypunch (totally mechanical between the keyboard and the 5 punch pins so not much use for computer interfacing). > > I'm also floored by the complexity of that Roytron punch! Looks like it > contains around one hundred separate parts. I'm convinced the punch parts > will have to be precision metal so while that's not quite "DIY" it might > still be a reasonable bit to CNC, mill or water-jet cut. > > It also looks like that punch has an escapement mechanism of some sort? > Seems like a simple way to keep regular spacing, but if course more parts > to buy from McMaster Carr or whatever. Some punches fed the tape with a sprocket wheel, one way to drive that is a suitably toothed ratchet wheel and drive pawl that moves it one tooth per punch cycle. As I said in another message, the Facit 4070 uses an accurately-machined (right diameter) capstan and pinch roller, the capstan moves the tape one chracter spacing for a certain number of steps (it _may_ be just one step) of the motor. I have another punch unit here which has the crank-and-interposer mechanism to punch the holes but has as sprocket with its own stepper motor to feed the tape. Different manufacturers did it in different ways. > > Question: did all tapes have indexing holes separate from the drive Eh? The sprocket holes _are_ the indexing holes, surely? > sprocket holes? Also is there a source for tape with sprocket holes anymore? Every punch I've seen (and own) can punch the sprocket holes on totally blank tape. Some insist on doing it (there's no way to punch a character without a sprocket hole), for others the sprocket punch is just another pin operated by the same type of mechanism as the data punches and you have to fire the solenoid at the right time if you want a sprocket hole. -tony
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Re: DIY Paper Tape Punch - Mechanism diagram?
> On May 1, 2020, at 11:31 AM, John Foust via cctalk > wrote: > > Were there any paper tape devices that did not use the sprocket holes > to move the tape? A lot of high speed optical readers use capstans and pinch rollers. But they still need the sprocket holes to be the source of the clock signal for latching the data. paul
Re: DIY Paper Tape Punch - Mechanism diagram?
Tony, maybe your collection can help me answer a puzzle: which side is "top"? By my reading, for 8-level tape, - ANSI and other US standards have three data bits / index / then five data bits - ECMA has five/index/three... :) https://twitter.com/33asr/status/1138758004747177984 On Fri, May 1, 2020 at 12:05 PM Tony Duell via cctalk wrote: > On Fri, May 1, 2020 at 4:48 PM Anders Nelson via cctalk > wrote: > > > > Wow, what a response! Really appreciate the docs and first-hand > experience, > > this is super helpful. > > I feel very greedy now. Looking arounds I have (not all working, but > all could be got to work, it's things like drive belts I need to get ) > > 3 Facit 4070s and an N4000 > A DEC PC04 > Two Data Dynamics units (1130 and 1183) which are 8-level punches > 3 Teletype BRPEs > A Trend Paper Tape Station (GNT 34 punch and Trend HSR500 reader in a > rack chassis) > A couple of Teletype Model 33 ASR's > A Friden Flexowriter with punch/reader > The punch from a Flexowriter on a rack chassis with its own motor. > > I think there's a couple of bare-chassis solenoid-operated punches > here too but I would have to hunt for them. > > And that's the 8 level ones. For 5 level (only) I have a Creed 444 > teleprinter and a Booth-Willmott Model 44 Keypunch (totally mechanical > between the keyboard and the 5 punch pins so not much use for computer > interfacing). > > > > > > > I'm also floored by the complexity of that Roytron punch! Looks like it > > contains around one hundred separate parts. I'm convinced the punch parts > > will have to be precision metal so while that's not quite "DIY" it might > > still be a reasonable bit to CNC, mill or water-jet cut. > > > > It also looks like that punch has an escapement mechanism of some sort? > > Seems like a simple way to keep regular spacing, but if course more parts > > to buy from McMaster Carr or whatever. > > Some punches fed the tape with a sprocket wheel, one way to drive that > is a suitably toothed ratchet wheel and drive pawl that moves it one > tooth per punch cycle. As I said in another message, the Facit 4070 > uses an accurately-machined (right diameter) capstan and pinch roller, > the capstan moves the tape one chracter spacing for a certain number > of steps (it _may_ be just one step) of the motor. I have another > punch unit here which has the crank-and-interposer mechanism to punch > the holes but has as sprocket with its own stepper motor to feed the > tape. Different manufacturers did it in different ways. > > > > > Question: did all tapes have indexing holes separate from the drive > > Eh? The sprocket holes _are_ the indexing holes, surely? > > > sprocket holes? Also is there a source for tape with sprocket holes > anymore? > > Every punch I've seen (and own) can punch the sprocket holes on > totally blank tape. Some insist on doing it (there's no way to punch a > character without a sprocket hole), for others the sprocket punch is > just another pin operated by the same type of mechanism as the data > punches and you have to fire the solenoid at the right time if you > want a sprocket hole. > > -tony >
Re: DIY Paper Tape Punch - Mechanism diagram?
On Fri, May 1, 2020 at 6:20 PM Hugh Pyle wrote: > > Tony, maybe your collection can help me answer a puzzle: which side is > "top"? By my reading, for 8-level tape, > - ANSI and other US standards have three data bits / index / then five data > bits > - ECMA has five/index/three... :) > https://twitter.com/33asr/status/1138758004747177984 As far as I know the 5-hole side is always the most significant 5 bits, the 3 hole side the least significant 3 bits. In other words the holes go : 76543S210 Where S is the sprocket hole and a digit is the bit number (bit 0 is the least significant bit). As to which way use the tape, with the tape feeding towards you, the sprocket hole is normally offset towards the right, that is the bits would read with the MSB on the left. I am not sure if that is universal though -tony
Re: DIY Paper Tape Punch - Mechanism diagram?
> On May 1, 2020, at 1:32 PM, Tony Duell via cctalk > wrote: > > On Fri, May 1, 2020 at 6:20 PM Hugh Pyle wrote: >> >> Tony, maybe your collection can help me answer a puzzle: which side is >> "top"? By my reading, for 8-level tape, >> - ANSI and other US standards have three data bits / index / then five data >> bits >> - ECMA has five/index/three... :) >> https://twitter.com/33asr/status/1138758004747177984 > > As far as I know the 5-hole side is always the most significant 5 > bits, the 3 hole side the least significant 3 bits. In other words the > holes go : > > 76543S210 > > Where S is the sprocket hole and a digit is the bit number (bit 0 is > the least significant bit). > > As to which way use the tape, with the tape feeding towards you, the > sprocket hole is normally offset towards the right, that is the bits > would read with the MSB on the left. I am not sure if that is > universal though > > -tony I suppose things get really confusing when dealing with 6 row tape (https://www.smecc.org/teletypes_in_typesetting.htm) paul
Re: tape baking
Agreed. They sure are pressed in, then riveted in for good measure. You’d have to drill them out first. Not an easy modification. Marc > On Apr 30, 2020, at 2:18 PM, Al Kossow via cctalk > wrote: > > On 4/29/20 10:01 PM, Curious Marc via cctalk wrote: >> Or replacing the posts with ones machined from Teflon or Delrin? > > The posts are staked in. You might be able to make tiny rollers to go over > the pins > Their working diameter isn't super critical >
Re: DIY Paper Tape Punch - Mechanism diagram?
Hugh said > I've cut Mylar tape with a Glowforge laser. It cuts very nicely but the > alignment is a major hassle, plus you can only cut ~15" of tape which > doesn't go very far. Not worth the effort. If you were to build a custom > linear drive it might work. But also very slow. That's very interesting. I had thought the smaller home shop lasers were generally for cutting perspex and thin plywood, rather than mylar sheet. Can your laser software import a DXF? If so I can send you a DXF of a test tape (in 15" segments) if you are interested, I would very much like to see the result. Steve.
Re: tape baking
On 5/1/20 1:59 PM, Curious Marc via cctalk wrote: > Agreed. They sure are pressed in, then riveted in for good measure. You’d > have to drill them out first. Not an easy modification. > Marc PTFE 2mm ID 3mm OD tubing is a standard size. That might fit. --Chuck
Re: tape baking
On 5/1/20 4:19 PM, Chuck Guzis via cctalk wrote: On 5/1/20 1:59 PM, Curious Marc via cctalk wrote: Agreed. They sure are pressed in, then riveted in for good measure. You’d have to drill them out first. Not an easy modification. Marc PTFE 2mm ID 3mm OD tubing is a standard size. That might fit. --Chuck All of the QIC-24 cartridges sitting next to me right now have posts that are machined with 1-2mm deep tape guides. I don't see how to install tubing over the posts and have the guides still do their job. As I noted, I have tried isopropyl alcohol to clean them off but they still stick. Is this something that baking will help with? Maybe using acetone instead of alcohol to wipe the posts down as well? alan
Re: tape baking
On 5/1/20 4:50 PM, Alan Perry via cctalk wrote: > All of the QIC-24 cartridges sitting next to me right now have posts > that are machined with 1-2mm deep tape guides. I don't see how to > install tubing over the posts and have the guides still do their job. > > As I noted, I have tried isopropyl alcohol to clean them off but they > still stick. Is this something that baking will help with? Maybe using > acetone instead of alcohol to wipe the posts down as well? If you wipe with alcohol, can you still see crud on the posts? If so, you'll need something stronger. Acetone might do, or MEK. But if alcohol cleans the posts, that's not the problem. You could try backing, but I don't think that will work either if the problem is in the binder. --Chuck
