3D Gears Math

SO here is the information for making 3D gears that all fit together. I used Sketchup for the design. All the gear convexities and concavities are 3-inch half-circles.

Screen Shot 2015-08-06 at 8.40.28 AM6-Spoke Gear

12-sided circle

6-inch radius (12-inch diameter)

Rotated 7.5 degrees

 

12-Spoke GearScreen Shot 2015-08-06 at 8.42.34 AM

24-sided circle

12-inch radius (24-inch diameter)

Rotated 15 degrees

 

biggear

24-Spoke Gear

48-sided circle

24-inch radius (48-inch diameter)

Rotated 3.75 degrees

 

Screen Shot 2015-08-06 at 8.54.54 AM Rectangular 14-Spoke Gear

12- by 24-inch rectangle

6-inch radius circles at ends

3D Gears

After having discussions with my math peeps, I decided to make gears. From scratch, in Sketchup. Many failures ensued. Thankfully, a Youtube video showed me the light (granted, I had to watch the video about 20 times).

Anyway, the gear ratio works (don’t ask me what that means), and different sizes of gears spin with each other. I even got fancy with irregular shapes (see the long gear) as well as gears with cut-outs (to save filament) and a gear with holes (to create abstract designs a la Spirograph).

August 2017
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