Leeway hardness tester instrument is light, easy to test, fast, easy to read, suitable for detecting a wide range of hardness of metal materials, and can be tested from different directions, very suitable for the field of large workpiece, assembly parts hardness test, its basic principle is that the impact body with a certain quality under a certain test force impact sample surface, The impact velocity and rebound velocity of the impact body are measured 1mm away from the specimen surface, and the voltage proportional to the velocity is induced by the electromagnetic principle.