Making timing pulley - putting theory into action

[Jonathan]

Impressive that your router is rigid enough for that. I did mine on the milling machine using the same process and it clearly put a lot of force on the spindle.

This time I used fly-cutter and rotary table.

I believe the term is form tool. Not that it's really matters...

Personally I would recommend this method than tooth drilling- less hassle - better tooth shape/finish.

I agree entirely. I found it difficult to get a perfect mesh with the belt. The theoretical values for the pulley blank diameter never seemed quite right.