Nautilus Launcher

Hey i am preparing to make a piston/Nautilus launcher for my robot but i can not figure out where to start with the cut out of the plexi Glass. I and figured out how to build the mechanism but how should i cut out the plastic gear. Currently i have access to a shopbot and a laser engraver.

I think you will find a nautilus cam template on this page:

You can expand the image to about any size you wish. If I remember correctly, the stroke that team 62 used was about 4.5 inches. Kids here made a sandwich out of their plastic, drilled a couple holes in the sandwich, ran screws through the holes to keep the pieces aligned, then cut the sandwich in the cam shape with a bandsaw, then Dremeled and sanded it to the exact shape. They did it this way to be sure the cams were identical so all the forces remained symmetrical.

If this doesn’t work you could always try a slip gear. Cut out nine consecutive teeth on a 36 tooth and the draw is about the same as a 4in drop cam.