61) A bolt is specified as M16x1.5x100. Number 1.5 stands for

62) _____ is a drop hammer used in forging

63) A drop hammer is used to forge a steel rod. If the energy transferred is 7500 Joules and the downward force exerted by the hammer is 15 tons, the distance the hammer travelled after striking is _____ mm

64) The process of increasing the diameter of a ring by forging is called

65) The accuracy of micrometer and caliper are checked by