Involute Helical Gears (CAD data)

This is a zip file containing a set of involute helical gears, from five teeth to 50 teeth. I've also added stl's of all gears if you want to print them directly, as well as step files if you want to make modifications to fit a specific shaft or spline.

The gears are all compatible with each other (module size 2.5mm) so any two gears will work with one another. Here are some other important attributes:

+Helix angle: 25 degrees

+Height: 10mm for all

+Pressure angle: 20 degrees

+All gears have undercut at the root of each tooth

Note on involute gears: involute refers to a curve obtained by attaching an imaginary taut string to a given curve (in this case, a circle) and tracing its free end as it is wound or unwound. The advantage to a meshed pair of involute gears is that the teeth of one gear roll on the teeth of the other, rather than rub on one another.

Note on helical gears: these are typically considered stronger than spur gears, as helical gears have longer teeth, and more teeth are engaged at any given time for a pair of meshed helical gears. Helical gears also produce an axial thrust in operation, so any transmission using helical gears typically needs a robust casing.