Helical Gear Fidget Toy

thingiverse

Now has a new little sibling at http://www.thingiverse.com/thing:2105705. !!!DEBURR THE GEARS AND REMOVE SHARP EDGES FROM THE GEAR TEETH!!! Don't put anything that can get hurt into the mesh point of gears! Not for young children, as ball bearings can fall out if not assembled correctly. Meshing helical gear fidget toy with a through hole for finger placement. Printing two identical gears will make them mesh at 90 degrees. Printing one right-hand and one left-hand gear will mesh straight on the same plane. The same housing works for both straight and perpendicular planes assemblies. Included is an STL file for a bearing race dressing tool. I passed some 180 grit sandpaper through the slots, then pushed it into the half toroids and rotated it back and forth to help smooth out ball bearing grooves. I used PLA for the gears and ABS for the housings. The little holes in the housing are meant to receive short pieces of filament. Cemented together using acetone on the ABS housings and inner cylinder. Epoxy or any decent glue can be used to assemble the housing pieces as well. There are a few versions of the inner cylinder. I had delamination issues when removing it from the printing bed. A little acetone on a paintbrush re-enforced the laminations fairly well. Spherical 4.5mm (0.177") BB ammunition is used for ball bearings. This package includes an OpenSCAD script for generating metric helical gear blanks. Written by me, and being released under the GNU GPLv3 license, besides this fidget toy. I exported the gear to an STL file, then imported it into TurboCAD and carved out the rest. If the assembly meshes a little tight, you might try scaling a difference of up to 0.5% between housing and gear (make the housing bigger). More than that, and the housing might "rock" over the ball bearings. Try printing a shim to your desired thickness and adding it to the housing assembly. In CURA, the shim can be cut off to the desired thickness. Something is very wrong if you need more than 1mm. If anyone wants a copy of the original TurboCAD files or an export to AutoCAD DWG, please make a request in the comment section. I'll zip it up and post it. Bill Of Materials for a pair of meshing gears: 4 housings 2 inner cylinders 2 gears 4 short pieces of filament ~9mm long. BB Balls to fill grooves Glue or Acetone (ABS)