26.4mm Hole - Slightly over 1 inch.
For 0.5 inch EMT (as seen in pictures)
Flat Bottom plus Base
Mirrored Sides plus Base
0.2mm layer, 2 walls, 40% infill
0.2mm layer, 3 walls, 15% infill
0.2mm layer, 2 walls, 15% infill
0.28mm layer, 2 walls, 10% infill