Eccentric Cam

Cams with complicated profiles (the technical term for the shape of a cam) can be complicated to manufacture, particularly with the type of equipment available in the school workshop. However, if all you want to do is produce a single up and down motion for every revolution on the cam, a circular cam rotating about a point offset from its centre (an eccentric), will often suffice. Note that the cam follower need not just move up and down - it can be a lever as illustrated.