Bolt Knobs (Parametric)

This customizable OpenSCAD/Fusion 360 file allows you to generate fully parametric knobs designed to accept either hex-head bolts or nuts, with support for both metric and imperial fasteners.

Perfect for:

3D printable control knobs

Jigs and fixtures

Tool-free assembly or adjustment knobs

Knobs have been defined to print without support.  Recess geometry includes provisions to create properly bridged holes, customizable for your print layer height.  Knobs should be oriented for printing with the “top” of knob resting on the print bed

Key Parameters:

Metric & Imperial Support: Includes built-in dimensions for standard sizes like M3–M12, and #4 to ½”. (OpenSCAD only, Fusion parameters will need to be entered individually for your specific bolt)

Hub & Bolt Recess Control: Customize the center hub diameter and height, and control bolt head recess depth manually or automatically.  Adjustable tolerances to achieve a press-fit or loose-fit of the recess.

Wings: Customize the number of wings and shape of the grip.  Higher values can be used to achieve a knurled appearance.

Surface Chamfers: Optional top and bottom edge chamfers for better print quality and aesthetics.

Requirements:

OpenSCAD (tested on version 2025.04.20) or Fusion 360

STL exported from OpenSCAD/Fusion or sliced directly via compatible slicers