KIM Uno /PiDP-11 plans...

[Mike Ross]

On Fri, Oct 23, 2015 at 10:26 PM, Alexandre Souza
<alexandre.tabajara at gmail.com> wrote:
>>> But a 11/70 replica needs two physical 'cosmetic elements': proper
>>> switches, and the white bezel/frame. The switches *seem* to be feasible to
>>> produce cheaply (I will know in a month with PDP-8/I switches...). The white
>>> bezel though brings me into unknown territory. 3D CAD (based on Museum
>>> Measurements), then injection molding or vacuum forming. Or any technique to
>>> produce a plastic object in medium quantities. All I know so far is that
>>> it's very feasible - and much cheaper to do than just a few years ago.
>
>
>    Jumping on the metro (since I'm so young) running:
>
>    Can't it be 3D printed? Or done with vacuum forming? Resin molding?
>
>    Are you talking the white bezel on this photo?
>    http://www.psych.usyd.edu.au/pdp-11/Images/11_35_draw.jpeg
>
>    It can be done easily:
>
>    - You can do it in a 3D prusa-something printer, if you divide it in
> printable blocks, and glue it afterwards.
>    - You can easily do that in Vacuum Forming. Since I never saw a 11/70 in
> front of me, I don't know the size/hardness requeirements, but I believe it
> is feasible
>    - You can create a cast mold in some material and use liquid resin (epoxy
> comes to mind since it doesn't shrink/expand on cure). Probably it would
> need a two-part positive/negative mold. Easily done if I had the original
> part on hand
>    - I haven't seen all the details, but I believe it can be 3D-cut into a
> suitable CNC machine, in wood or plastic.

Actually, thinking about it, there are two approaches, and they're both valid:

1. Take a lot of trouble, spend a lot of money, and produce as close a
replica of the original as possible.
2. Do what he did with the PiDP-8/I; something 'close enough' which is
reasonably accurate and evokes the original very nicely, but doesn't
even pretend to be a precise replica.

I don't think it even *needs* a bezel IF option 2. is selected. Print
a different perspex, add a few more switches, paint them purple
instead of brown, add a couple of rotary switches... put it in a
wooden box again. Job done very simply.

But whether it's 1. or 2. I don't see any strong argument for NOT
making it full-size. But we can all talk about it; he's the poor
bugger who actually has to do the work :-)
Mike


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