A workbench (1) has a removable vise (3) and a workplate (5) separate from the vise and provided with apertures (6) for clamping elements. A jaw assembly (15) having a fixed vise jaw (16) and likewise a jaw assembly (17) equipped with an adjustable jaw (18) can be screwed onto a vise base (14) so as to resist all twisting forces. The screw fastenings (28 to 30) are such that they can also serve to attach the jaw assemblies to the workplate (5), using the apertures (6) in the latter for that purpose. The vise as a whole can be mounted in a rotary seat (2) where its mandrel (13) can be clamped at different levels and rotary positions, with the further possibility of having the rotary position fixed in the lowest position of the vise in a manner suitable for maintaining parallelism with another rotary vise similarly mounted (not shown in figure).