Gear Generation

I have a rack and pinion gear specified as:


2.2 DIA
2.6 Pitch DIA
2.92 Outer DIA
13 Teeth 5 DIM. PITCH
Standard 20° Stub Tooth
ADDEN. 0.16
DEDEN. 0.2
Whole Depth: 0.36
Corrected ADDEN. 0.17
CORDAL Thickness of Tooth 0.313

9 Full Teeth 5 D.P. 0.6283 C.P.
20° Stub Involute Rack
American Standard
ADDEN 0.1600
DEDEN. 0.2000
Whole depth 0.3600

Is there some gear generator that will work with these parameters? All the gear generators I have tried online give me an outer diameter of 3, rather than 2.92.

Have you tried Rayflectors gear generator? Also FreeCad has a gear generator add-in

I can’t find Rayflectors. Is the spelling right?


Found the link


I created this long time ago, the terms you posted are different. (35.0 KB)


Oddly Rayflector will only allow a minimum of 17 teeth.

17 teeth is a minimum for a standard profile. Below that you get into extra undercuts to permit meshing.

There is a gear generator here that creates the correct undercuts for gears with less than 17 teeth. The only problem is it only outputs lines for the tooth profile. You’ll need to trim the OD to the size you want.

Thank you very much.

I believe I have figured out why the generated gears do not fit my plans. The plans specify “American Stub Tooth.” Using formulae I have found on line targeted towards this gear, the numbers seem to match up with those on the plans

Does anyone know of an “American Stub Tooth” Gear generator? Or a diagram showing how to translate the parameters into a stub tooth gear?

If you only have this one gear and rack to create, the output from the page I linked above should be easy enough to modify. You only need to modify one tooth, extrude then a circular array.

These settings give the correct pitch diameter,and deden for the gear, just need to trim the OD to 2.92. Editing the rack is simple.

This shows the sizes in Rhino.

The problem I am running into is the calculator gives an Inside Diameter that is too small (as well as an outside diameter too large). This causes problems with the adjacent part of the shaft. I can trim the outside, as you suggest, but the inside remains problematic.

Is the inside diameter the pitch diameter minus 2x the Deden? Is the corrected ADDEN causing the problem? You can set a minus size for the clearance for the calculator! -0.254 should be corrcet?

Thanks much. The negative value worked.