The file 'Knob Round Shaft With Grub Hole Pilot 3D Printer Model' is (stl) file type, size is 342.0KB.
A version of the knob where the D shaft has been made rounded and a hole added for a grub screw of 2mm diameter.
If you are using a particular screw to grip the shaft, you may need to drill and tap the grub screw hole.
I uploaded one with and without the mark.
The shaft diameter is about 6mm
Knob_round_shaft_with_grub_hole_and_mark.stl | 425.9KB | |
Knob_round_with_grub_hole.stl | 424.6KB |