UNO/Breadboard cradle

I get tired of wires popping off my projects when I move them around.

I have done the bit where you screw breadboards to a wood plank and that was never very satisfying - it was either too big and clunky or one breadboard less than the number I eventually needed. (Feature creep is a fact of life for makers!) I also wanted my UNO mini breadboard to be on the same plane as my add-on breadboards.

This is a modular system where you can start with an UNO cradle and add as many breadboard cradles as you need. If the project grows you can add middle units as needed.

Key features:
the unit-to-unit attachment holes are on 4" centers, 3/8" of an inch from the support surface. I sized the holes and pocket for #6-32 (M3.5x .6) hardware.

There is one unit designed to support a single board, a "side" unit that can be paired for two boards, and a "middle" unit that can be used to expand to as many boards as you need.

The unit breadboard size is 6.5" x 2.25" (165 mm x 57 mm). Each adde