Eventually I got the idea of using a router table.
It looks something like this: basically a gear blank is secured to what I call a trapezoid guide, and with the clever placement of a couple of fences it makes a very useful gear cutting setup.
I’m very happy with the end results, so keep watching to see how I make this jig.
Before getting in the shop, I use AutoCAD to create a template that evenly divides the circle according to the number of gear teeth.
If you don’t have AutoCAD available, this step can be done with a good old protractor. That’s how I lay out the small gear because there isn’t any space to secure a template.
Depending on the tooth count, the trapezoid guide has to be shaped accordingly. To determine the angles, take 360 degrees, divided by the number of teeth – I’m making a 60 tooth gear, and divide by 2 because we cut on both sides of the trapezoid.
So 3 degrees is the angle the miter saw needs to be set at.