The first part of the ladder holder consists of two 2-by-4 wood pieces about 16 inches long. You'll attach each to parallel joists through two angle brackets and connect them with a threaded rod ...

This leaves two mounting holes on either side of the lens to attach threaded rod using nuts. The assembly is capped off with a square of acrylic (plexiglas). Quick and clean.

Rubber washer, 2. Brass washer, 3. Threaded locknut w/set screws. Hand tighten the threaded locknut. Use a screwdriver to tighten the set screws on the locknut.