The first thing you need to make is your cutting tool. I modify a regular Dremel router attachment to make this job easier.
I modified the attachment by gluing a piece of 1/8" plexiglass to the base. I just used regular foam safe CA to do this.
Drill a hole in the plexiglass where the bit will exit. Drill the hole to fit the brass tubing you'll glue into place in a moment.
Next up, I glued in a short piece of 3/8" brass tubing. Diameter is not terribly important, but your router bit needs to fit inside. Glue the piece so that 3-4mm sticks out of the plexiglass. Make sure to glue it from the topside. You don't want the glue fillet on the 'working' side.
Finally, screw the modified router base on to your Dremel.
Why on earth did you add this plexiglass base and tube? The plexiglass allows you to router out larger areas, and the tube allows the router to follow a pattern.
