Abstract: A fixture for supporting a workpiece during machining including an L-shaped, rigid, primary body member forming two panels or faces of the assembled fixture. The fixture also has two secondary panels which, when mounted to the primary body member, form a cube. The secondary body members are detachably mounted permitting their removal for the design and mounting of a workpiece frame within the fixture. One panel of the primary member has a device for clamping a workpiece support frame to the fixture. All external fixture locating and indexing devices are mounted on the primary member and are thereby permanently located with respect to each other.