This OpenSCAD can be used to generate knobs with captive nuts of any size, and with multiple options:

• Number of flutes (for gripping).
• Depth of flutes.
• Flute bottoms to stop fingers catching on face plate.
• Stand offs ("in-built washer" or knob stalk).
• Screw thread and nut sizes.
• Fillet (edge rounding) configuration.

Version history

V2

• Adds fillet configuration.

V1

Initial release.

Prusa

I3 MK3S

Doesn't Matter

No

0.2mm

Any

• If you print with a standoff then it will need supports. Personal preference is to print it upside down and support the net recess.
• Depending on the application you should adjust the infill and number of perimeters.
• Works great with flexible filament for applications where occasional bumps will happen.