Mushroom Head Machine Screw Mushroom Head Screw is also known as truss, oven head, stove head, and oval binding head. Mushroom Head Screw that we offer has a low, neat appearing large diameter head with excellent design qualities. Mushroom Head Screw can be used to cover larger diameter clearance holes in sheet metal when additional play in assembly tolerance is required. Pan Head is usually suggested as a substitute for Mushroom Headscrew.