[Ian, Sander, Daniel]

I designed some guardrails that go 3" above the M6 tapped holes of the shelf above the optics tables in B111B. I used 1/8" thick, 1/2" wide aluminum bar. There were 3 piece types (all holes centered along the 1/2" width):

Vertical bar: 4" long; 0.24" (C drill) diameter hole 0.5" from bottom; 0.27" (H drill) diameter hole 3.5" from bottom

Long horizontal bar: 36" long; 0.27" diameter holes at 0.78", 1.5", and 3 more holes with a regular 250 mm spacing beyond 1.5" to match the shelf hole pattern.

Short horizontal connection bar: 19" long; 0.27" diameter holes 0.375" from side and 2 more holes with 9.125" spacing

This short horizontal connection bar is designed to be replaced by a patch panel if desired.

Ian helped me drill some holes and Sander helped me install the connection bars.

We were not able to install 1 long and 1 short horizontal bar because the seeder breadboard overhangs the shelf by ~1". 

See attached photos.