Abstract: A weld stud having a cylindrical section permitting engagement by a stud welding gun, joined by a shoulder on to a threaded shank covered up to the shoulder by a cap nut made of plastics, wherein the cylinder section changes through a chamfer into a shoulder and the cap nut is provided with a resilient lip, which stretches to cover the chamfer when the cap nut is brought into contact with the shoulder. The threaded shank may have a ridge close to the shoulder which engages in a corresponding annular recess inside the cap nut. The cap nut may have a coaxial, preferably conical, projection at its end opposite the lip.