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HAMMER AND TYPES OF HAMMER USED IN BENCH WORK

 Hammers are used to strike a job or a tool. They are made of forged steel of  various sizes  ( weights ) and shapes to suit various purposes. A suitable range would be from 0.11 to 0.33 kg for light work such as clinching small rivets and dot punching, 0.45 kg of chiseling, 0.91 kg of heavier work such as chipping, the popular sizes of  bench work being 0.33 to 0.45 kg.

A Hammer consists of four parts namely peen, head, eye and face. The eye is normally made oval or elliptical in shape and it accommodates the handle or shaft. The end of the handle which fits into the eye is spread or split by forcing a metal wedge into to prevent the hammer head from flying of the handle during striking. The handle is made of elastic wood or bamboo and is so shaped and sized that when gripped it gives an easy feel to the hand. This "feel" is known as the "balance of the hammer. A well balanced hammer "feels" just right when the handle is grasped at the correct point. The face is hardened and polished well, and is slightly convex, instead of  flat to avoid spoilage of the surface of the metal to be hammered by the sharp edge of the flat surface. on an average , the handle should be 250 to 325 mm long. The length of the handles for light hammers is 200 to 260 mm. That for heavy hammers is 380 to 450 mm. 


Hammers


Hammers are classified , according to shape of the peen, as ball peen , cross peen, and straight peen hammers. 

Ball Peen Hammers : This is most common form of hammer and is sometimes called engineer's hammer or chipping hammer. The Peen has a shape of a ball which is hardened and polished. This is hammer is chiefly used for chipping and riveting. The size of the hammer varies from 0.11 to 0.91 kg. 


Ball peen hammer


Cross Peen Hammers : This is similar to ball peen hammer in shape and size except the peen which is across the shaft or eye. This is mainly used for bending, stretching, hammering into shoulders, inside curves, etc. The size varies from 0.22 to 0.91 kg.


cross peen hammer


Straight Peen Hammers : This hammer has a peen straight with the shaft, i.e, parallel to the axis of the shaft. This is used for stretching or peening the metal. The size varies from 0.11 to 0.91 kg.


Straight peen hammer


Soft Hammers : It is used where it is necessary to strike a metal a blow with the minimum damage to the surface, a soft-hammer , called mallet, is used. mallet heads go by the numbers or by the diameter of the head. They are made of raw hide, hard rubber, copper, brass, lead or most commonly - of wood. 


Soft hammer


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