Mechanism modeling

A mechanism modeling kit in which flat non-metallic simulations of machine elements may be assembled into demonstration working elements for designing machinery and teaching the design thereof comprising at least one sheet, said sheet being pre-cut to provide punchable machine elements and links of different sizes and shapes, hollow grommets for heading in assembly of said elements and links, a grommet heading tool for tighteningly heading said grommets, wherein said grommets are loosely headed around at least one element and one link for pivotal movement thereof, said tool including a frame, an anvil and a crimping element supported by said frame, said crimping element being rotatably mounted in said frame for controllable crimping movement toward said anvil.