Automatic Trip Hammer Our Automatic Trip Hammer is produced as per BS1377: Part9: 1990 for carrying out the Standard Penetration Test (SPT). The Automatic Trip Hammer comprises following parts: A) A weight made of steel and provided with an axial hole with a diameter which is 3 mm to 4 mm larger than that of the guide rod. It is of 63.5 kg. B) A pick-up and release mechanism to ensure that the weight has a free fall of 760 mm and shall not influence the acceleration and deceleration of the weight or the rods. C) An inner guide shaft to permit the weight to drop with minimal resistance, and to ensure the weight stikes the anvil squarely. D) An anvil made of steel with an integral threaded portion to connect squarely and rigidly on to the top of the uppermost extension rod.
