This is an extension focusing knob for laser diodes that are mounted on many small laser cutters/engravers. It makes it easier to precisely focus the laser and protects your fingers from the high-power beam emitted. You can either 3D print or laser cut the knob.
The diameter of my laser knob was 16mm, so I designed my extension knob with an inner diameter of 16.5mm to account for my tolerances. If you have better/worse tolerances or a larger/smaller knob on the diode, feel free to scale up or down.
I also uploaded a modified SVG of this in case anyone who has only a laser cutter wants to cut it out of plywood or acrylic.
Step 1 - Measurements
I measured the knob with digital calipers, which came to 16mm.
Step 2 - Design in Fusion
I designed a base model for the laser diode, which I used to model the knob around. I created circular sketches and extruded a simple wheel. I then created a pattern for the gears and used Sketch -> Circular pattern to duplicate it. I repeated this to make the cutouts and added fillets inside.
Step 2 - Design in Inkscape
In Inkscape, I created a simple gear with no center hole using Extensions -> Render -> Gear. I then scaled it to ~32mm (the outer diameter of my 3D-printable version). I added a circle and scaled it to a radius of 8mm (diameter 16mm, like in the 3D printed version). I saved the file as an Inkscape SVG.