Wanted: Second Processor dimensions for 3D printing

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ikilby
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Wanted: Second Processor dimensions for 3D printing

Post by ikilby » Fri Jul 13, 2018 9:34 pm

After selling all my BEEB stuff years ago, I am building my collection again. Just received a Model B today from Ebay and re-capped the PSU and she works fine. Ordered some upgrades like 1770 Disk interface, Datacentre and speech chip. Also going to try the Pi second processor and this is where i need help.

I have access to my own 3d printers and i want to build a external enclosure for the Pi (will be using Pi 3). I want to replicate the Acorn 2nd processor enclosure that was used for Prestel, 2nd 6502 and Z80, but I have not seen any dimensions etc.

Are there any technical drawings of that enclosure, or failing that can someone take some measurements for me so i can start a 3d print design.

Added a picture of one to illustrate what I am looking for.

Cheers
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Acorn_CamCoProA.jpg
Last edited by ikilby on Sat Jul 14, 2018 9:32 am, edited 3 times in total.

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BigEd
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Re: BBC Micro collection starts again

Post by BigEd » Sat Jul 14, 2018 7:42 am

I can take amateur measurements of a Z80 copro I have. Are you seeking great accuracy and fidelity? Do you want to know radius of all the rounded edges and so on? I have a ruler, but not a micrometer.

The service manual gives only the very basic bounding box:

3.6 Outside dimensions
Height 72mm
Width 207mm
Depth 346mm

Just checking: are you able to print something so large?

BTW: Welcome to stardot! It's worthwhile I think to edit your post title to include 'Wanted: Second Processor dimensions for 3D printing' or similar.
Last edited by BigEd on Sat Jul 14, 2018 9:01 am, edited 1 time in total.

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Elminster
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Re: BBC Micro collection starts again

Post by Elminster » Sat Jul 14, 2018 8:43 am

I think it would need to print in sections and join it.

I always watch in envy as other Retro machine have had new moulds made and near original cases pumped off the production line.

Edit. And don’t forget there is a Intro topic for new members, and Welcome :D
Last edited by Elminster on Sat Jul 14, 2018 8:44 am, edited 1 time in total.

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BigEd
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Re: BBC Micro collection starts again

Post by BigEd » Sat Jul 14, 2018 9:03 am

Just realised a great labour-saving factoid: the second processor is very much the same shape as the Beeb. So once you have the width measurement, you can measure a Model B for the rest.

ikilby
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Re: BBC Micro collection starts again

Post by ikilby » Sat Jul 14, 2018 9:31 am

Thanks Guys.

With that info i can make a start.

BigEd those dimensions are fine & yes I will probably have to print in several sections, but thats the challenge of design :)

I will share when I get somewhere with this, but I warn you I am slow.

When I sold my original BEEB stuff I had a Acorn 2nd 6502 processor and a Z80 processor. Wonder how much that would cost me to replace now !!

There is a Prestel unit on Ebay that I may be on for a donor unit and to use as a template for design - depends how much gets bid.

cheers guys.

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BigEd
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Re: Wanted: Second Processor dimensions for 3D printing

Post by BigEd » Sat Jul 14, 2018 10:33 am

It would be great if you would share your work, once you get there - even if it takes ages. In the future, there will be even fewer bits of kit on ebay, but printers will be larger, faster, and cheaper. And we'll all wear silver suits.

colonel32
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Re: Wanted: Second Processor dimensions for 3D printing

Post by colonel32 » Sat Jul 14, 2018 3:38 pm

How would 3D printing fare with the beeb texture? I know it’s a bit of a tricky texture, from my attempts to clean deep-seated gunk out of it.

Would this have been a shot-blasted mould for the original cases?

I’m sure you could take the corner radii from a Model B case - even if the cheese wedges were slightly different, it would actually be better to have it match the main case.
Last edited by colonel32 on Sat Jul 14, 2018 3:40 pm, edited 2 times in total.

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