Abstract: A clamp for a tooling ball having a base plate, a ball stand secured to the base plate, and a tooling ball bound to the ball stand. A clamp assembly rotatably sandwiches the tooling ball and supports a scale, or the like, for rotation about the tooling ball. A method for establishing a plane for lay-out purposes with a clamp assembly supporting a scale and rotatably sandwiching a tooling ball bound to the tool ball stand supported on a base plate. The method comprises positioning a pair of the clamp assemblies on a jig under construction such that the scale is in a position to measure vertical distances from the jig under construction. The method additionally comprises situating an independent scale across the two scales of the pair of clamp assemblies such that a horizontal edge of the independent scale defines and identifies the established plane for lay-out purposes.