A capstan operated wedge grip where the grip body moves upwards under the capstan action , closing the jaws on to the sample. This action minimises the preload applied to the sample by the grips. The jaws are spring loaded to the capstan rod, this eliminates backlash and allows the jaws to move when load is applied.

Various jaw sets are available allowing flat samples to 28mm thickness and round samples up to 36mm diameter to be tested. Flat jaws are cut with a 90 degree 1.5mm pitch pyramid tooth form. Round sample jaws are cut with a buttressed tooth form with either a 1.25mm or 2mm pitch. Jaws are easily interchanged, requiring only the loosening of two screws. Special jaw sets are available to customers specification.