Updated to work with the latest version of Autodesk Fusion, now supporting part designs and additional help text. 

Generate helical and spur gears with full control, with customizable addendum/dedendum, backlash adjustment, meshing parameters, and positioning.
Internal and external, rack, worm, and herringbone gears. 

Parameters
Gear type - External, Internal, or Rack. Worm gears count as external gears
Module - Gear module for sizing, tooth spacing on pitch circle, calculated normal to the teeth by default
Helix angle - Angle of the gear teeth measured from the vertical, 0 for spur gears, angles close to 90 for worm gears. 
Teeth - Number of teeth, worm gears usually have only 1
Gear width - Height/length of the gear

Standard - determines if calculation is based on the pitch circle or helix. Normal is what you typically want.
Pressure angle - Contact angle at which teeth contact. 20 degrees is the norm, but different values may be desired for different applications like high load 
Backlash - clearance between teeth, used for compensating print tolerances or for adding desired play
Addendum - Height of the teeth from the contact circle, usually set to 1
Addendum - Height of the teeth from the contact circle, usually set to 1.25 for clearance 

Plane - Plane to build the gear on 
Center - Center point of the gear
Direction - Should the gear be built on top of, in, or behind the selected plane
Rotation - Rotation of the gear around the center
Offset - Shifts the gear in or out of plane 

Info - gear calculations

Usage
With the Add-In running, you will find the Helical Gear + command in the solid create dropdown.
Activate it and fill in the desired parameters.
You can check the preview checkbox to get a live preview, but for more complex gears it might be easier to keep it turned off.
For creating a worm gear, set the helix angle to a high number, 90 minus the worm angle. A matching worm and wheel would be for example 80 and 10 degrees. 
Check gear parameters in the info tab. Confirm the gear by pressing OK.

Support
For additional support or customization, contact us at info@phos.systems or create a ticket on the GitHub page.