In one embodiment a cam-activated bench vise comprises a fixed jaw having a first gripping surface, a moveable jaw having a second gripping surface, a threaded rod for providing movement of the moveable jaw relative to the fixed jaw, a hinged split nut for selectively engaging the threaded rod, and a lever actuated cam that rotates a beveled plunger against a first end of the split nut, forcing a second end of the split nut to engage a bevel-mouthed receiving block which causes the split nut to close and to engage the threaded rod.