About this 3D model

I needed simple and sturdy door handles that would allow my hand to pass through, I couldn't find any. I'm sharing this little work done on Freecad. I printed it at 80% of its size with 5 walls, 5 lower and upper shells and 30% infill for safety. The screw holes are 6mm chamfered, which can be enlarged with a drill if you increase the walls...