DEC H960 stabiliser feet. Have some questions.

Noel Chiappa jnc at mercury.lcs.mit.edu
Mon Jan 8 07:25:12 CST 2018

```    > From: Steven Malikoff

> That's the first actual photo I've seen of the foot, and I see what you
> mean.

Oh, I can take more, then; let me know what you need.

> Let's regard the inner vertical surface where it mates to the rack as
> the normal surface.

Right; that's our reference plane.

> If you have a length of something straight .. clamp it with a .. clamp
> to that inner surface

Umm, not possible. There are two diagonal (in the horizontal plane) ribs
coming off that surface, so there's no way to clamp anything vertical to
it. The _front_ (outer) surface, parallel to the reference plane, I could get
to (and the clamp is a good idea). Here's what I wound up with:

http://ana-3.lcs.mit.edu/~jnc/tech/jpg/StabilizerMeasurement.jpg

(Yes, yes, I know, tha assumes the back face of the square is parallel to the
front; it is, pretty much - I checked with a vernier calipers.)

So the vertical distance from the horizontal plane at the bottom of the
stabilizer, at its tip, to the bottom of the 'outer surface' (as above), is
17/32". The distance from the plane of the 'outer surface' to the end of the
stabilizer is 7-9/16". The distance between the reference plane and the 'outer
surface' is 7.14mm (one thing I _could_ get a vernier calipers on :-).

Also, it turns out the right-hand vertical face of the stabilizer is _not_
perpendicular to the reference plane! The foot angles in slightly. The outer
vertical surface is a plane along its entire length, so it's hard to notice
unless you put a square on it directly:

http://ana-3.lcs.mit.edu/~jnc/tech/jpg/StabilizerAngled.jpg

(Sorry about the lens distortion; wanted to show that the square was along
the reference plane.)

I couldn't get anything clamped on to make the measurement, but the tip of
the stabilizer is about 1/2" (to a /32nd, or so) in from a vertical plane
perpendicular to the reference plane, and situated at the right-most location
on the foot (i.e. along the edge of the square, in that photo).

> A pencil rubbing on paper, or paper creasing slong eges then drawn over
> with a ruler can also help to get angled surfaces.

Sorry, couldn't figure that out?

> Another thing, CAD can make good use of non-perpendicular measurements.
> So if you're able to measure something across a diagonal or at some odd
> angle, then please do so. It can be used to triangulate and improve
> other taken measurements, like a point cloud.

What other measurements should I take?

One easy/obvious one is from the right-hand outer bottom corner of the
stabilizer to the left-hand bottom corner of the reference plane: that's
8-9/32". (A lot of these corners are rounded, so exact measurements are a
matter of choice....) The top inner corner of the right-hand face is 9-11/32"
from the bottom outer corner of that face (same corner as above).

Noel
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