The material for these was $30 worth of 1/2'' HDPE sheet and a bit of 1/4'' scrap from the plastic supplier's scrap bin .The nuts and bolts are 304 ss with nylocs ,About $10 worth .Steel for the mounts was $10 plus a few bit s of flat from my scrap bin .+ My ancient stick welder .
The rectangular white sections are welded to 1/2'' thread sections and tighten up from the inside .When they are tightened they can't slip left or right as they sit between two blocks .I rotate them vertically to lock them in place over the top mount bar ,the bottom bar is just a firm fit ....an advantage of using the HDPE plastic ....it doesn't rattle , rust or knock off paint.
The inside ,reinforced with 3/8'' of ply and bolted to the inside of the pannier .The ''nuts'' are 1/2'' HDPE cut out with a holesaw .The work like little hand wheels .I put dome nuts on the end when I tighten everything up.
The panniers themselves are US army hotboxes , cheap ($45 each ),light (aluminium) and waterproof (when you finally find the right sealing rubber profile !!! ).There is a thread on ADV Rider about building them .
