This is a little baroque door knob I designed and sculpted in Blender 2.8 as a replacement for the original that broke.

It was printed vertically at a 0.12 mm layer height with standard PLA.
The knob has a diameter of roughtly 2.5 cm (or one inch) but you can scale it in your slicer.

The part is designed to be used with a threaded insert that you will have to insert in the part with a soldering iron : just place your threaded insert above the hole in the part an touch the insert with your soldering iron. The insert should set in place strongly in the plastic part with that little bit of heat.
The hole for the insert on the 3D model is exactly 5.85 mm diameter.

It has served its purpose on a bathroom cabinet for several months and I hope you will like it!