http://lumberjocks.com/projects/207842#comment-2822866

Few days ago i finished building my belt sander (see review here), based on Matthias Wandel design (original plans here).
this machine is great solution for sanding wooden gears, which i use in many of my projects. I though that now that i can sand them conveniently, I need to find a way to produce them in my workshop. usually is go to a CNC owner and cut it there for a lot of money.
so based on my tilting router lift and table (see review here), that was built also by Matthias Wandel plans (here), I’ve built an attachment to my router table fence – a pin router.
the idea is very simple – any template can be copied in 1:1 ratio, snd any shape can be made, inner side or out, given that the corners are not smaller than the bit diameter.
I took a quick release chuck from an old driver, attached it to a board, and made it clampable to the fence with the built in knobs. I’m using a chuck so i can use any bit that i want with its relevant pin – from 1 mm to 13. right now I’m using 3mm bit with 9mm height, which gives me the ability to copy some small very small gears in fine finish.
to prevent overloading the bit, i do 2 or 3 passes. the lift is very accurate and raising the bit keeps the same location and cut almost without showing vertical lines.
in the pictures you can see the small plywood pinion (small gear), which was made with a CNC machine, and my copy of it in solid walnut. the result came up perfect. what you see in the image is how the gear came out – no sanding required and it works great. and the best part: it took less than 2 min to produce. include all the setup! if i only came with this jig 2 years ago… I belive it’s faster than any CNC i ever seen at work.
Ive added another configuration, a higher one, this to allow bigger and longer bits to be used. i turn the chuck around and use the four upper screw holes.