A 'good-enough' H960 |d|i|g|i|t|a|l| PDP11 masthead replica

steven at malikoff.com steven at malikoff.com
Thu Jul 9 20:21:31 CDT 2015

Wow, I wake up and you blokes on the other side of the world have been busy during the night working at getting a bunch of details for me :)
Thanks Barry, Pete, Paul, Noel, Bill, Adam for your responses - the measurements and photos are exactly what I need. I'll go through them in
detail soon and adjust the drawing.

Paul: I will revisit the postscript file and fix up mine from it. There's a reason I try to avoid splines in my CAD drawings, a long time ago
I did DXFs for laser cutting some keyrings (see http://web.aanet.com.au/~malikoff/jeep/keyring) using splines. The cutter operator replaced
them with arcs owing to their software not being able to process it properly. Since then I've avoided splines for any drawing I do that has a
chance of being exported as a DXF (or SVG for that matter) that is to be fed to a CNC device.
I'll also follow up on your observation about the variations in the handbooks font, I'm sure I'll find them on bitsavers.

Noel: fabulous! Thanks very much for the measurements, appreciate the use of calipers. I do agree that efi is a great DEC seller, I've bought
some bits from him. I'll reluctantly pass on the blank panel though, our dollar is weak and the international postage rates have gone through
the roof in recent times.

Bill: wood would suffice I guess, but unlike wood, styrene sheet always has perfectly consistent working properties and as a long-time scale
modeller I am extremely familiar with using it. I also have a number of large sheets of the stuff, in different thicknesses, ready to use.

Adam: I appreciate your photos very much. One thing that intrigues me is the end-on photo IMG_3161. It appears the top edge projects further
than the bottom by a tiny bit leading to a tapered appearance, but I assume the plane of the printed inset panel is parallel to the exterior
mounting surfaces. If you don't mind I'll load that into CAD and do some overdrawing to determine if that's the case. Your lighting is good
so I'll take the RGB values for the colours. BTW the first image won't load for me: '... cannot be displayed, because it contains errors'.

Pete: also teriffic photos, thanks as well! Nice measurements especially the letter heights. That will be invaluable to make it a better drawing.
I think I'll need to do a drawing of the whole unit and then have the measurements checked so I don't misinterpret your figures. Appreciate the
use of a micrometer too. A common method of determining radii is to use an engineers radius guage. Failing that, try fitting a series of
circular objects (coins etc.) which can then be measured with calipers or micrometer.

So thanks again everyone, a super response.


More information about the cctalk mailing list