This flange is intended to slip over a pipe and be held on to plywood. The original use was to make an old English lamp post as a prop for a parade. 3" ABS pipe is used to support the lamp housing.
Flange2.stl has a 90 mm inner_dia which works well for a 3" diameter ABS pipe. The depth iis 80 mm with a 4 mm flange thickness. The screw hole radius is set at 2.5 mm which works well with #8 screws.
Used glue on the bed as it is a 7 hr print with Cura, much longer with Slic3r PE.