A mechanical component with a broad, convex upper surface and a narrower stem, resembling a mushroom. This geometry is common on structural rivets, emergency stop buttons, and engine valves. The wide head distributes clamping loads over a larger area or provides an easy target for manual actuation.
Heard on the job
The drawing calls for a mushroom head rivet here to prevent the sheet metal from tearing under vibration.
Related terms
Poppet valve
A directional valve consisting of a flat disk on a stem that lifts away from its seat to permit flow.
Head
The static pressure of a fluid expressed as the height of a liquid column, or a cylinder cover.
Blank
A piece of raw material pre-cut to a rough size and shape before final machining or forming.