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Thread: Looking for the PDP-8/I Control Panel Assembly Bezel Casting drawing

  1. #1
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    Default Looking for the PDP-8/I Control Panel Assembly Bezel Casting drawing

    I am looking for the PDP-8/I front panel bezel casting drawing, for a possible project to recreate the bezel in 3-D printing.

    I looked on BitSavers in the /PDF/DEC/PDP8/ section and I see that the PDP-8/I Assembly Parts List is drawing A-PL-8I-0-0. There I see that the Control Panel Assembly drawing is E-AD-7005554-0-0. And, I see that the Control Panel Assembly contains the Bezel Casting Rework drawing E-IA-7406188-0-0.

    I believe I would be looking for the Bezel Casting Rework drawing E-IA-7406188-0-0 in order to obtain all the dimensions necessary to describe the bezel for 3-D printing. However, so far, I have not been able to find a copy of the Bezel Casting Rework drawing.

    Can anyone offer up a pointer to where I might be able to obtain a copy of the bezel drawing? Also, has anyone else ever investigated creating a copy of the DEC PDP-8/I front panel bezel? If so, I would appreciate any info or pointers on that project, so I don't go off and re-invent something that has already been accomplished.

    Thanks for listening. Thanks in advance for any advice or pointers that you may have to offer.

    smp

  2. #2
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    If you don't find the original drawings then you're set to recreate it from measurements of an original panel. I'm doing the same as you but for an -11 console.
    I haven't seen an 8i panel but if it's anything like the other DEC consoles I've seen, it's likely the same relatively simple pattern that doesn't use compound curves.
    The tools I use are a digital caliper (the larger the better), angle gauge, radius gauge, height gauge and surface plate.
    If you don't have the original in front of you, you can still get good results but it's more time consuming. Getting someone else to measure their panel is ok but they may not have the same tools. There are ways you can help them, for example sending them a pdf of radius corners to print and cut out. Or, put a round coin flat against surfaces and details being photographed. Then you can always scale from the coin diameter even when it appears as an ellipse.

  3. #3
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    Thanks very much for your reply - at least it keeps my request on the top page of posts for a little while longer!

    Believe me, if I had an original example, I probably would not be looking to create a 3-D printed replica! I have nothing, and I am looking for the bezel drawing, so I can investigate what it may cost to reproduce one. With no original (in any sort of shape) and no drawing, I am reduced to making guesses, and I'd rather not be guessing.

    If no pointers to the drawing are available, does anyone have a PDP-8/I bezel - whole or in pieces - that could be measured?

    smp

  4. #4

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    Quote Originally Posted by smp View Post
    If no pointers to the drawing are available, does anyone have a PDP-8/I bezel - whole or in pieces - that could be measured?
    I do have one that I could try to find some time to measure (or maybe even model) for you.

    Vince

  5. #5

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    I started a drawing...

    8iBezel.png

    As is often the case, it looks way better than it is. It's still missing the slot for the panel artwork and all the other attachment stuff on the backside and edges. (You have mount the lights PCB, the switches PCB, and then there are also threaded holes to mount the whole assembly, which hinges out for service.)

    You'll probably want something for the light guide thingy too.

    Vince

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    Thanks very much for your effort, Vince.

    Of course, the goal is to end up with a drawing that I can provide to a 3-D printing business, and get an estimate of the cost to produce one (or more) of these bezels. That drawing would have to include all the bits that you indicate you don't have yet. If you are up for it, I would love to see what your model looks like when complete.

    smp

  7. #7

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    Bezelb.png

    OK, I had a go at more of the drawing. The slot for the artwork is there, as are mounting points for the light mask and for the switches PCB. (The lights PCB actually mounts to the light mask.) I put lower mounting tabs for the light mask, but not the slotted angle brackets that mount to the #6-32 holes at the top. I couldn't think of a good way to make that simpler to fabricate and still have the depth be adjustable.

    It's drawn in Sketchup, so the holes aren't drawn threaded (that's really hard in Sketchup). You'd have to drill and tap, though I did stick undersized holes to help center things and a few text labels on the drawing to make it clearer what to do. Mostly everything is #6-32, I think, except the bottom right hole (left as you look at the back) is #10-32.

    The tabs for the light mask are just drilled, but there are #10 screws that go into threads in the light mask there. I also modified the tabs so they're part of the bezel, rather than the original assembly of a screw, spacer, and bar stock.

    It's drawn from my (sometimes crude) measurements, so it may need some tweaking to line up perfectly with vintage parts. (Just think of it as untested.)

    Vince

  8. #8
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    That is a great drawing Vince!
    Don't worry about the threads, the "in thing" (literally) for 3D prints these days are nutserts, which are heated and pressed in, or you can press-fit and superglue instead. Hackaday recently had an in-depth article on them.
    10-32 and 6-32 are readily available: https://www.ebay.com.au/itm/150PCs-SAE-Rivet-Nut-Kit-Rivnut-Nutsert-Assort-Set-1-4-20-10-32-10-24-8-32-6-32/363055279052
    Also
    https://www.ebay.com.au/itm/AWS2-103...a/254713607804

  9. #9

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    Quote Originally Posted by smp View Post
    Thanks very much for your effort, Vince.
    You are welcome. (It's something I've thought of doing from time to time but never made time to actually do.)
    Of course, the goal is to end up with a drawing that I can provide to a 3-D printing business, and get an estimate of the cost to produce one (or more) of these bezels. That drawing would have to include all the bits that you indicate you don't have yet. If you are up for it, I would love to see what your model looks like when complete.
    There are quite a few challenges to 3D printing something like this. It's a lot of area and a lot of plastic, which is probably why Shapeways wants over $300 to print one. A less expensive printer would need the thing broken down into printable pieces that could be assembled later. A fair amount of support material might need to be printed (and then removed). It's big, so printing will take a good long while. (And so on.)

    I'll probably putter with it a little more and eventually put it up on my 3D page, but at least I think we've got most of the dimensions recorded now (modulo any measurement errors I've made).

    If you are masochistic, the files are online here:
    http://svn.so-much-stuff.com/svn/trunk/3D/8IPanel/
    The Sketchup drawing is in inches; if you want mm, be sure to get the right STL file.

    Vince

  10. #10
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    Thank you very much for all this effort, Vince!

    Whew! $300 is a bit more than what I was hoping the cost might be. Did you actually submit files to Shapeways for an estimate?

    I am not familiar with any of the CAD tools, so would you please indicate specifically what subset of your files would need to be submitted to a 3-D print house for an estimate?

    Most of all, please post back here with any updates that you make, so I can stay up-to-date with the latest files.

    Thanks very much, once again!

    smp

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