Abstract: A hydraulic clamp embedded in a T-slot of a machine tool bolster plate, has a T-slotted piston rod end which fits continuously within the T-slot of the bolster plate. Using a T-configured member secured to the underside of a die shoe, and slid into the T-slot, actuating the hydraulic clamp draws the shoe downward, firmly clamping it against the bolster surface. If, instead of a T-configured member, and I-beam member (in effect, a double T) is used in a die shoe having a T-slotted undersurface, the clamping force is extended over the entire length of the I-beam. The effect is to avoid distortion of the die shoe. In addition to the surface friction attendant to the present distortion-free clamping, positive resistance of sideward displacement of the shoe is provided by the T-slot edges. When the present invention is not employed for clamping, the T-slotted surfaces of the bolster plates are unencumbered and may therefore be used and cleaned in an ordinary manner.