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

Noel Chiappa jnc at mercury.lcs.mit.edu
Fri Jul 10 20:28:16 CDT 2015

    > From: Steven Malikoff

    > I'm not sure I interpret Pete's measurement of 33.1mm from the back of
    > the flange to the front of the box, correctly. Noel also says the same
    > 'from the back of the flange' so I must be missing something here.

Hmm. I thought for a moment I'd misread my calipers, but I checked again, and
3.80 is correct for the thing I measured, which is (on your IMG_3161) from the
lower end of i/j to the upper edge of d/g. So clearly we must be using
different definitions of 'flange', or something - or maybe his unit is
somewhat different from mine?

Here are the rest of the measurements from that image:

'k' = 'm' on mine, at 1.15 cm. That downward projecting flat (at one end of
'l' and 'm', which is at 90 degrees to the thing I'm calling the 'flange', the
thing with thickness 'i', which is completely horizontal - along two axes - in
that image) is cut back a bit, in the direction normal to the screen, from the
end of the upper part (at the left edge of 'k'), which is why they look, from
the slight angle in that image, like they aren't in a common vertical plane
(normal to the screen) - but they are.

'l' = 2.6mm; 'h' is 10.64 cm; 'd' is 5.73 cm; 'i' is 2.70 mm.

'g' looks to be about 4.6 mm; I should mention that the corner below it (at
the upper end of 'i') is not a right-angle, but a rounded thing with a fairly
considerable radius - something on the order of 3.5 mm. 'j' is 3.35 cm.

The edge labelled 'flush with bottom edge' is indeed flush with the left-hand
end of the horizontal flange.

On IMG_3162, 'q' is 1.16 cm; note that the left edge of 'q' is almost, but
not quite, in a plane with the right hand edge of 's'. The left edge of 'q'
is about 3.4 mm to the left of the right edge of 's'. 'u' is 1.13 cm. (This
turns out to be 'z' in the third image.)

Note that the little tab (the thing you're measuring 's' on) projects up
under the 'plate' which you're measuring 'u' on; i.e. the maximum width of
that tab, 't', is up underneath that plate. I can't measure it because it's
not a sharp angle where it meets the vertical surface (i.e. in the plane
normal to the screen) up under there; rather, it's a radiused corner (which
you can see in the next picture).

On IMG_3144, 'y' is about 1.56 cm (bit hard to measure that one; I should
have used a flat to give me good end point at the RHS to measure to); 'x' is
1.25 cm; 'v' is 9.1 mm (ditto); 'w' is 2.85 mm. 'a' I can't really give you
directly, but I can give you the distance from the upper end of a, to the
upper end of 'w', which is 7.96 cm; add that to 'w' and 'v' and that will
give you 'a'.


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