Designing a Singlespeed Cog: Getting to know Fusion 360

Printed 19T Singlespeed Cog
Small project modeling single speed bicycle cogs to the ANSI standard. It was a fun project to get more familiar with Fusion 360.


I didn't have to design a cog from scratch. Its well know that bicycles use an ANSI #40 chain which means 0.5" pitch. Knowing that, I looked in the Machinery's Handbook and found detailed drawings and equations for sprocket design. I really didn't feel like doing all the math by hand so I typed it all into an excel spreadsheet. You can download the spreadsheet here. You can also download the finished stl files from from my account on (

Dimensioned image of an ANSI sprocket Tooth Form.
Also includes basic measurements for standard sizes.
I converted the measurements to mm for quick reference.

Equations to calculate values shown in the dimensioned image above.

Screenshot of Sprocket Calculator in Excel. Auto-calculates
all values based on  Pitch and Number of teeth.
Red values are ones used in Fusion 360.
Download Link.

Modeling in Fusion 360:

Design Process in Fusion 360

Sketch of sprocket tooth. Dimensions are for a 19T cog.

3D Printed Final Design:


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