The original SCAD file interprets the diameters as a radii, and does not accept fractional diameters, so odd diameters are impossible. With this minor fix they are now possible!

The v2 version corrects a cog length issue.

Note there was a Customizer problem within Thingiverse before; if you still have trouble it can be worked around by installing OpenSCAD and running Customizer locally, using the instructions here:

• Download the latest version of OpenSCAD (which includes Customizer)
• Under Edit, Preferences, enable Customizer
• Under View, uncheck 'Hide Customizer'
• Open the SCAD file downloaded from Thingiverse
• On the right side of the app, enter the custom values you want. The 3D image will update automatically
• When ready to generate the STL file, first render the image (e.g. F6), then export as STL.