Abstract: A portable vise is disclosed including a beam along which a hydraulic cylinder assembly is positionable to adapt the vise to a wide range of work pieces. The hydraulic cylinder assembly includes a carrier slidably engaged with a beam flange and which is lockably engageable to the beam during a clamping operation. A lock or stop includes a pair of leg members insertable within a selected pair of beam defined apertures. The cylinder assembly includes a lever operated pump with a self-contained fluid reservoir. The beam is supported on a turntable in turn carried by a pedestal having a wheel equipped base. For clamping articles with curved surfaces, a pair of supplemental jaw plates are provided, each having an irregular clamping surface to assure positive engagement with a clamped article.