This cup holder was made for a Dolomite walker. May fit other walkers as well if it has a strap that is 1/8 x 1-1/2" (38 x 3.2mm). Assemble with 3 sheet metal screws #6 x 1/2" (3.5 x 12mm). Two screws are installed from the outside (through the clip into the cup), one is installed from the inside (through the cup into the clip).
Use wall thickness of 1.5mm for extra strength and to ensure the narrow part of the clip is solid. Print as shown: cup upright, clip on its side, to give the clip the maximum strength possible.