Abstract: A seat belt anchorage has a tubular housing adapted to be mounted on support structure of a vehicle. The housing has a cylindrical wall. A nut is axially slidable along the inner surface of the cylindrical wall. The housing has a transverse wall at an inner end of the cylindrical wall. The transverse wall has a tapered surface. The transverse wall has an annular abutment ring inwardly of the tapered surface defining a central opening. The nut has a tapered side in contact with the tapered surface of said transverse wall and an end in contact with the abutment ring. A bolt has a shank extending through the opening and threaded into the nut. The bolt has a head exteriorly of the housing and a collar on the shank between the head and the abutment ring. A seat belt supporting plate is mounted on the collar. The bolt in normal use is tightened to draw the tapered side of the nut against the tapered surface of the transverse wall and to draw the collar against the abutment ring.