Goujon de culasse

A stud is a headless threaded rod fixed in a part, onto which another part is fitted and secured with a nut.

Screwed or pressed permanently into one component, it locates the mating part and clamps it when the nut is tightened — wheel studs are a common example.

Studs are used on wheel hubs, cylinder heads, manifolds, and housings. The correct stud matches the thread, length, and strength grade.