Abstract: Apparatus adapted for adjusting the position of articles held together by tensioned fasteners such as bolts having a head, a threaded shaft and a nut into which the shaft is threaded includes first and second washer members that are receivable in a stacked array on the bolt shaft between the bolt head and an adjacent surface of one of the articles. Each of the washer members has a diametrically extending semi-cylindrical groove in the surface thereof which faces the other washer member. A cam lever has opposed cam pins of arcuate non-circular cross-section receivable between the washer members within the grooves. Movement of the cam lever to first or second positions thereof will cam the washer members away from or towards each other respectively, thereby applying tension to or releasing tension from the bolt so as to clamp the articles together or release them for movement relative to each other.