Explain why bolts of uniform strength are preferred. Draw sketches of two different types of bolts of uniform strength

bolts of uniform strength: if a shank dia.is reduced to a core dia.as shown in fig. the stress become same through out the length of the bolt. Hence impact energy is distributed uniformly throughout the bolt length, thus relieving the threaded portion of high stress. The bolt in this way becomes stronger and lighter. This type of bolt is known as bolt of uniform strength.Another method of obtaining the bolt of uniform strength is shown in fig.in this method, instead of reducing the shank dia.an axial hole is drilled through the head down to

the threaded portion such that the cross sectional area of the shank becomes equal to the area of the threaded portion If bolts of uniform strength are not used a large portion of impact energy will be absorbed in the threaded portion and relatively a small portion of energy is absorbed by a shank. This uneven distribution of impact energy may lead to the fracture of the bolt in threaded portion .hence bolts of uniform strength are preferred.