Hmm, try saying that 3 times real fast... The New Yahoo! Search - Faster. Easier. Bingo http://search.yahoo.com

B&C Computervisions in California not only has a LOT of plotters, but knows quite well about the gear problem. IIRC, the plotters are common in mechanism between Atari, Commodore, and Radio Shack. I think they were made by Alps? They differ somewhat in case and interface, but otherwise parts interchange readily. Anawho, we are probably talking about this plotter which mechanism is the same as that of the Atari 1020. It is a 40-column plotter which has four pens, black, red, blue and green esconced in a revolving cylinder not unlike that of a 4shot Derringer pistol and which prints on a 4" or so roll of register paper. The pens, paper, and parts for the plotter are all available new at B&C. If we are talking about the same plotter, then off you go. Otherwise.... errr... disregard this message and the pedant behind it's creation. ;-) Regards, jeff -----Original Message----- From: cctalk-admin(a)classiccmp.org [mailto:cctalk-admin@classiccmp.org] On Behalf Of Ethan Dicks Sent: Thursday, April 17, 2003 10:20 AM To: cctalk(a)classiccmp.org Subject: Re: Wanted: TRS-80 PC-2 Pocket Computer Plotter pens --- steven <tosteve(a)yahoo.com> wrote: Please post the source, if you find one. I have an Atari plotter and a Commodore plotter (model 1520) that use the same mechanism and the same pens. What I could _really_ use is a source of the gear that fits directly on the X and Y motor shafts. I have tried going to local RC car and model train shops, but they don't carry gears. This thread has come up before, but I still don't know how to sit down and accurately determine the physical characteristics of these gears to the satsifaction of a mail-order gear vendor. I can mic the shaft, I can count teeth, but the rest eludes me. I did buy a handful of plot engines from a surplus house. 80% had fractured gears. :-( -ethan The New Yahoo! Search - Faster. Easier. Bingo http://search.yahoo.com

I used to have the 1020 model and wrote some cool stuff for it. Here's a nice idea for a project. I did this one about 15years ago, but still have the warez I coded. 3feet plastic fiber optic cable (shielded). 1ea fiber optic detector (is a vpot) 1ea 9pin joystick port connector. Wire the output of the IRD to the potentiometer port on your Atari/commie/whatever. Strip the end of the cable to expose about 1/8th inch. Wrap electrical tape around the end of the cable til' it is the same diameter as the pens. Remove a pen from the plotter and substitute the fiber for it. The exposed end of the fiber should protrude a little through the metal spring return for the pens. The rest should be obvious, but put a porno magazine 1/2 page into the plotter and shine a BRIGHT light at the page. Run my program. It stepps the plotter, samples the returned light for that spot and assigns a greyscale to it, posts that pixel to the screen, stepps the potter, samples, etc til' the image in in memory. Works pretty well. I used an emitter/detector set from Radio shock to do this back in 85' or 86'. It does not pick up text well (low rez destination screen). Greens and blues don't register well which is one of the reasons for the BRIGHT light. I used a 100watt bulb in a flexible desk lamp. The Radio shack pens are compatible with this mechanism, but they are a little thicker at the end which makes them a tight fit in the Atari version. Still work though. If your pens dry out in storage, boil them for a few minutes in a pot of water. That should rejuvenate them. Regards, Jeff <SNIP> AFAIK, the plotter engine is abolutely identical. I used to buy my pens and paper at Radio Shack. I still have an unopened box of paper and a tube of unopened pens. Hope they still write. :-) Bingo. I wrote a few programs for the Commodore 1520 about 16 years ago. Unfortunately for emulation purposes, the C= ROM code is embedded in a 6502-family microcontroller, so any emulation has to be by inspection, not by, um, "borrowing".

Look up gears/gearing in Machinery's Handbook for a definition of all the defining parameters for gears. At 07:20 AM 4/17/03 -0700, you wrote:

Hello Ethan, re: Machinery's Handbook That was the complete title. Check out these links ... http://www.google.com/search?hl=en&ie=ISO-8859-1&q=Machinery%27s+Ha… http://search.ebay.com/search/search.dll?MfcISAPICommand=GetResult&ht=1… At 08:23 AM 4/18/03 -0700, you wrote:

Damn - forgot this until just after I hit 'send' on the last message: the Central Hive of all things gear-related is at Boston Gear, www.bostongear.com They include some very nice and detailed tutorials to help you find the part you're looking for. Cheers John

--- "Jeffrey S. Worley" &lt;Technoid(a)30below.com&gt; wrote: It is, but not a long-term one. $4 when I got them. Because most of the mechs had bad gears, too. So far, my total count of working gears is very close (+/- 1) to the number I need to keep the plotters I own working. At some point, I will not have enough gears. As it is, I spent a wad of money to buy a pile of spare parts with about 3 good gears. :-( No, but plotters that once had good gears, now have bad gears. They fail. Perhaps it's thermal expansion problems, perhaps it's stress, but these gears do not last. The material is so thin at the bottom of the splines that they develop a longitudinal crack along them. As other have said, perhaps it's a poor choice of materials or perhaps it's a poor match of shaft diameter to gear I.D., but for whatever reason, it's a common problem to this plot engine. -ethan The New Yahoo! Search - Faster. Easier. Bingo http://search.yahoo.com

That is the title... It's a thick reference book (over 1000 pages IIRC) that includes just about every useful table for mechanical engineering -- thread cutting, gears, etc. I found an old copy (1943 IIRC) for \pounds 1.00 in a second-hand bookshop. The problem with a copy that old is that it doesn't include things like standard metric screw threads. On the other hand the information that is there is still valid, at least for the sort od engineering I do. It's like old copies of the 'rubber bible' (the CRC Handbook of Chemistry and Physics). The last few figures of some of the constants may well have chnaged by now. But I can't work to that accuracy at home :-) -tony

--- Tothwolf &lt;tothwolf(a)concentric.net&gt; wrote: I doubt if we'd have to have gears made-to-order. It's mostly a question of measuring the critical dimensions in a manner that is meaningful to a gear maker. I was hoping to find a way to order these from someone's catalog, then make an offer to buy a quantity bag and distribute them to folks on a variety of lists including the CBM Hacker's list and here. I don't mind buying q. 100 and being a gear-go-to-guy, but I still don't know how to take a physical gear and sit there with a handful of measuring tools to get _all_ of the critical dimensions (number of teeth and shaft diameter are trivial...) -ethan The New Yahoo! Search - Faster. Easier. Bingo http://search.yahoo.com