China does not have cheap labor. China has a Yuan (mostly) locked to the Dollar. Anyway, You will end up spending all of your money on the tooling. Even crappy simple molds are *expensive* - for the standard switch handle (I am guessing you are talking about the paddles on a PDP-8/e and such), I would bet that just the mold would start out at five hundred bucks, from a discount tool and die shop (with a resulting horrid job). For a good professional job, get into four figures. -- Will

On Aug 24, 2007, at 2:36 PM, woodelf wrote: Well, America has big wages if your title begins with "chief" and ends with "officer". Rest in peace, American middle class. I have an interest, but only for a handful. Will is right; the molds will be the killer. I worked on a commercial product a few years ago that used a two-part plastic chassis that was about the size of a small book. The two halves were very, very simple...no weird shapes, and not difficult for mold design. The "cheap" aluminum molds cost us about $10,000 to have made, and the good stainless steel ones (last much longer) were to cost about $18,000. Molds for small parts such as switch handles will be cheaper, and there's a side benefit to their small size: we might be able to design one mold that can make several different types of switch handles (PDP8/e-PDP11/20 style, PDP11/45-PDP11/70 style, etc) in one shot. DEC didn't use that many different styles of switch handles. There's still the front-end-loaded cost of having a mold cut, but after that, the community would never again have problems getting switch handles. -Dave -- Dave McGuire Port Charlotte, FL Farewell Ophelia, 9/22/1991 - 7/25/2007

some pictures of the science museums store... including pictures http://news.bbc.co.uk/1/shared/spl/hi/picture_gallery/07/ in_pictures_technology0s_hidden_past/html/1.stm some big iron there..

On 8/24/07, woodelf <bfranchuk at jetnet.ab.ca> wrote: I have worked mostly with various PDP-8 switches, and the 11/70 switches. The PDP-8 switches are nothing unusual, for the time, but I don't know where one would find quantities of them now. The 11/70 switches are rather ordinary C&K switch bodies with uncommon, but standard, squarish stamped sheet-metal snap-mounts. New C&K switches are a few dollars each, unless you can find them surplus (which I did at the Mansfield Hamfest last year, at least for the non-momentary, snap-action switches for my 11/70 panel). I don't know how to describe the older switches, except to say that they were the rather common slide-switch type of the era, with the bakelite slide and square stem that is topped by a ridged curved actuator area. Lots of them were used for power switches for 1960s and 1970s appliances. The reason the DEC switch handles were these odd levered affairs was to fit over an ordinary switch. Personally, I could use some 11/70 switch covers - I have a panel with _zero_ actuators. At the moment, I have standard C&K black paddles on them, which is unaesthetic, but functional. If 11/70 actuators were to be made, I would probably be interested, but I'm unconvinced that at present prices, it's economical to make a hobbyist run of them. Perhaps in the medium-term future, should fab-at-home-type hardware continue to drop in price, the equation will look more favorable, but right now, I don't think it is. -ethan

Rumor has it that Dave McGuire may have mentioned these words: Doubtful... he isn't lost! ;-) <wink> The individual you're thinking of was Larry Berg of Purple Computing - he's still in "business" as it were - his business model is kinda like a "open source hardware" model... it works for him, tho. http://www.pfranc.com/ This is kinda ontopic - even tho he doesn't support Tandy Model 100/102/200 laptops anymore (he used to sell memory upgrades & whatnot for them) he still uses them for daily tasks around the shop, including one that runs his plastic injection moulding machine. Hope this helps, Roger "Merch" Merchberger -- Roger "Merch" Merchberger | "Profile, don't speculate." SysAdmin, Iceberg Computers | Daniel J. Bernstein zmerch at 30below.com |

From: "Doc Shipley": If I am understanding you correctly, I'm looking for "Authentic, preferably close to Original". It's necessary to locate the parts to render the stuff operable (though I am lazy about actually debugging it), and preferable to preserve the stuff, or at least the experience of using the stuff, as much as possible. So, the switch handles seem like a big deal, since they are a primary aspect of using the machines (at least until a working mass storage device is attached). I assume people will want them the original size and shape, and ideally the correct colors. The casting process generates a fair number of "rejects". Most of the handles I have cast can be made functional, in the sense that (possibly with rework) they can be made to operate a front panel switch. Perhaps one in three of the handles I've cast is visually free of voids, bubbles, or other defects. I could probably do better with more control of the process, etc. None of the handles has had the correct color. The closest I got was a wierd pinkish apricot color, when what I was shooting for was something between terra-cotta and pumpkin. No two batches of plastic were close to the same color. (The dyes are not very soluble, and come in an almost unusably concentrated form which I haven't found a way to dilute.) Sure, and I'd replace a gate with one with a newer date code (if I had to), as I don't think that affects the experience or result noticably. More than likely, an old bulb with a similar new bulb that is still comercially available. Heck, I'd even (functionally) replace a rack of DF32s with a semiconductor replacement, since it really isn't good for the old drives to run them (especially intermittently). But if replacement DF32s (or parts for them) were readily available, I'd want to use the real thing. There's my $.02 :-). Vince

From: "woodelf" <bfranchuk at jetnet.ab.ca> I have successfully cast passable switch handles (in ones and twos) without using injection molding. I used silicone rubber to make molds from existing actuators. The colors are where I got stuck. I haven't been able to make actuators come out the color I want, not to mention repeatably. If one can't get repeatable results, then it would be necessary to cast a set of them together (so they'd come out the same color). Not terribly, but no-one stocks full size slide switches much anymore. (Isn't this one of our perennial discussion topics?) Vince

From: "David Griffith": I got as far as buying the Rit, but I haven't done the experiments to figure out how good the result is, let alone to get reproducible results. Do you know the part numbers for full-size switches? Are they stocked, or are they "we can get these if you order enough"? Vince

I've seen some parts created with Fused Deposition Modelling, the so-called "3D printer", and was quite impressed. A variety of materials are available, but ABS seems to be the most common. There are several companies now that provide outsourced prototype manufacture using this technology, similar to the short-run PC board houses. You send them the CAD file, and they send you the parts. Color could be a problem, and you might have to settle for painting them yourself. They shouldn't look too bad with epoxy paint if you can get the color match. A quick web search turned up these guys, who sell such paint for modelmaking in small quantities in a variety of colors. http://klasskote.com/paint_store.html --Bill

All this talk about DEC switch handles has me wondering exactly what is being discussed. When removed from a front panel, exactly what does one of these doodads look like? Cheers, Chuck

On 8/27/07, Vincent Slyngstad <vrs at msn.com> wrote: That model goes with the -8/L/e/f/m, and most likely the 11/20. The "long rocker" type I recall from the -8/S/i, and the Digital Lab. The "triangular" type goes with the 11/35/45/70. I don't recall if the Straight-8 uses identical actuators as the ones in the auction above, or not. The tips look the same, but having never seen them out of context, I don't know if they are identical, or merely similar. Personally, if someone ever does replicate actuators, I'd be primarily interested in the -8/L/e/f/m type first, and the -11/34/35/70 type second. For now, though, I'll sit on the sidelines until someone claims success and starts listing prices. -ethan

On 26 Aug 2007 at 21:10, Vincent Slyngstad wrote: Ah, many thanks--now I understand. Would it be possible to mill out the profile in a big hunk of polycarbonate and then slice the paddles off like slices of bread? The result could then be painted. I wonder if you could cast some out of zinc-aluminum alloy using a lost-wax process? Metal ones would be more durable. Cheers, Chuck

On Sun, 26 Aug 2007, Vincent Slyngstad wrote: And the next time you clip your nails you'll wind up with notches in your nails. -- David Griffith dgriffi at cs.csubak.edu A: Because it fouls the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail?

For this much trouble, it would probably be worth just making a proper mold. For the paddle types, and maybe the others, I can see it would be possible to make an el cheapo two part mold, then have a small amount of milling of the finished parts. Two part molds are a whole bunch cheaper than three part molds, which is probably what the originals used. -- Will

If that's the book I think it is, then I have it, and the machine certainly looks as though it should work. One day I intand having a go at making it (but I am short of circular tuits at the moment). Of course making the machine is only half the problem, you still have to make the mould. As regards a lack of machine shop, I am pretty sure David GIngery has written a set of books on making a machine shop from scratch. But my experience is that the people who can do this (a) have access to machine tools and more importantly (b) have been machinists for many years and thus have a lot of experience as to what is possible, what is imporatant, and so on. I don't feel many people could make a lathe from scratch having never used one. I buying a small-ish lathe totally out of the question for you? Yes, a good one is expensive, but it's versatile, and will last for a very long time with reaonable care. -tony

Roy J. Tellason wrote: I'd want to go with a full sized shop, all the nice machining stuff I have seen are rather large scale steam engines. :)

Mr Ian Primus wrote: I have rapid-prototyping gear. It's expensive to make stuff, so quantity is out of the question, but I've used it for making one-off hard drive mounting rails. Peace... Sridhar

Its all in the tooling... Even if the tooling were available cheap or free, a molder would still charge a setup fee that might be tough to stomach. Once that is done, and the machine tuned to make decent parts (typically machines and molds need tweaking, or voids and warps will result), the parts are really cheap. Might as well make 10000 of each. Not sure about this rant... -- Will