Abstract: An assembly is provided for holding a printed circuit board between spaced surfaces. The assembly comprises a plurality of wedge-shaped members slidably mounted end-to-end on a rod, with at least one of those members being movable in a transverse direction relative to the rod and to its respective adjacent members upon effective shortening of the rod to thereby bring a clamping surface of the transversely movable member into contact with a printed circuit board and to apply a clamping force thereto. The retainer is disposed in a recess of a base structure which includes an abutment formed at one end of the recess. The retainer is activated by rotating the rod thereby urging the slidably mounted members towards one another. Bevelled washers are disposed on the rod between the abutment and one of the end-most members which, when compressed upon tightening of the retainer, provide a force tending to urge the members away from the abutment.