Abstract: For supporting heat and vibration producing machinery on grouted foundations, high-strength plastic chock halves, which may be glass-polyester laminates, are used beneath machinery conventional steel sole plates resting on conventional plastic grout. The plastic material is characterized by a greater flexibility and much lesser thermal conductivity than steel, so they serve as barriers to the transmission of heat, while their flexible resiliency protects the foundation from vibrations attendant to operation of the machinery so supported. Leveling steel shims inserted between the chock halves do not impair the uniformity of the flexible resiliency they afford at each support point. Fretting wear of the machinery bed plates appears to be completely eliminated.