I needed some door handles for my new bathroom that was being installed and figured these could be 3D-printed with no issues. These feature a modern (and thus also simple) design that has some slight chamfers on the inside. They were screwed in from the back, through predrilled holes in the doors with a 3.5mm diameter plasterboard screw.
I've also included the two templates that I made to position them correctly where I wanted them on the door in case this could be useful to someone.
The author hasn't provided the model origin yet.