3-Lobe Fidget Spinner

thingiverse

I decided to give designing a fidget spinner a try. I opted for a straightforward 3 lobe design that would fit a standard 8mm x 22mm x 7mm bearing found in inline skates. This design was created using OpenSCAD. Print Settings Printer Brand: Printrbot Printer: Printrbot Simple Metal Rafts: No Supports: No Resolution: 0.1 Infill: 20% Notes: I've added a heated bed to my Printrbot Simple Metal, so I could print in ABS. The pictured print is using Gizmo Dark Blue filament. I printed at 240 degrees C and kept the bed at 85 degrees C. On my Printrbot with 20% infill and 0.2mm layer height, this prints in about 45 minutes. Changing to 0.1mm layer height raises print time above 2 hours, but is worth it if you want a nice finish. Post-Printing Adding Bearings After printing, you can clean up the print if you want, but mostly it's ready to add the bearings. You need four bearings for a 3-lobe spinner. Place the spinner on a hard flat surface and set a bearing level on one of the holes. Press hard using a small hard surface like a flat piece of wood. Be careful not to press on the walls of the bearing as you may damage it. Repeat for the other three bearings, and you're done. Print Some Hub Caps It's useful to have a couple of caps that fit in the center bearing and let you hold the bearing without putting any friction on it. I printed out two of the caps from this thing: https://www.thingiverse.com/thing:1800902 Much thanks to sLpFhaWK (https://www.thingiverse.com/sLpFhaWK) for his excellent work. How I Designed This Using Math in OpenSCAD I included the OpenSCAD file I used to generate the STL files on this thing. You can alter the variables to change the lobe diameter, length of the arms, and other stuff. I commented the code pretty well so hopefully you can follow it. The model takes a really long time to render. I think I have some weird math in there. Some values for the variables can kick up an error during rendering, but I've provided comments noting safe values to use.