Summary of following long story: mistake was made, but ended up 
being a feature. The design for the long laser cover should take 
the 1/16" expansion of the silicone into account. And no typos 
this time.

Short cover version still to be fixed... (PJM, 2011)


Long story long:

A typo in the initial drawings submitted to the shop (the starting 
block for the "body base" part was incorrectly listed as 0.5" 
instead of 0.625") led to an interesting story...

Jeffrey constructed the main body and body base out of a single 
piece of delrin, and the typo caused it to be too short. As a 
direct result of this 1/8" difference, the location of the holes 
labeled B (which are centered on the baseplate and allow the side 
walls to be attached) were off by 1/16". With this, the front 
wall's fiber and DB9 features didn't match up properly with the 
\main body when it was attached to the walls (it was off by 1/16").

Jeffrey notified me of this fact, and to fix it we changed the 
position of the holes labeled A in the front wall drawing by 
drilling them 1/16" closer to the "top" of the laser. This dropped 
the crucial elements into alignment. However, we didn't realize at 
this time was that the initial typo was the culprit, and shaved the 
bottom off the front wall so that it would match up with the 
bottom of the base as it was drawn (the difference was meant to be 
1/8", so we removed 1/16").

So, the outcome of the mistake and fix is that the height of the
cover is actually 1/16" shorter than the drawings indicate (with 
the material removed from the side of the cover which will sit on 
the table). 

When I realized what had happened, I made a new fix using a 
0.064" laser-cut piece of acrylic. This didn't end up being 
necessary since the silicone expanded by about 1/16" and had to 
be trimmed anyway.

So, we need to incorporate this "feature" into the design for future
users.