General Purpose 3D Printable Herringbone and Spur Gears Set

thingiverse

I've put together a set of general purpose 3D printable gears that should cover a large range of purposes. I've included herringbone, spur, helical, worm, and rack gears. I've included a variety of different sizes of STLs for each type of gear, so ratios between 1 and 10 are achievable. Herringbone gears are available in two thicknesses, 15mm (thick) and 6mm (thin). You can scale parts to fit your needs, and you can scale thickness and radius independently, but don't mix herringbone gears from the thick and thin sets as the teeth won't mate properly. Spacing between the centerlines of any two gears should be the sum of their pitch radii, with each gear's pitch radius being (pitch × numberOfTeeth) / (2π). As is, all herringbone and spur gears have a pitch of 4mm. So, for example, a 48-tooth gear and a 12-tooth gear should be spaced (4mm × (48 + 12) / (2π)) = 76.39 mm apart. I've included SLDPRT files that can produce whatever variants of these gears you'd like. If you want prime numbers of teeth, just go into Equations and change the value for "nTeeth". Most parameters are modifiable without requiring modification of sketches or features. Easily adjustable parameters include number of teeth, pressure angle, tooth pitch, wall thickness, shaft size, etc. I've also included STEP files. All parts are designed to be printed without support, with the exception of the worm gears. If you increase the skew of the herringbone or helical teeth, those might need support. Let me know if you find any problems. Full write-up with explanations of theory and design decisions and instructions for modification of SLDPRT files is available at http://www.travisllado.com/2018/03/general-purpose-3d-printed-gears.html