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20 pounds (9.1 kg) and 10 pounds (4.5 kg) sledgehammers
|Other names||Sledge Hammer|
|Used with||Wedge; Hammer wrench|
A sledgehammer is a tool with a large, flat head attached to a lever (or handle). The head is typically made of metal. The sledgehammer can apply more force than other hammers, due to its large size. Along with the mallet, it shares the ability to distribute force over a wide area. This is in contrast to other types of hammer, which concentrate force in a relatively small area.
The handle can range from 0.5 metres (1 ft 8 in) to a full 1 metre (3 ft 3 in) long, depending on the mass of the head. The head mass is usually 1 to 3 kilograms (2.2 to 6.6 lb). Modern heavy duty sledgehammers come with 10 to 20 pounds (4.5 to 9.1 kg) heads. Sledgehammers usually require two hands and a swinging motion involving the entire torso, in contrast to smaller hammers used for driving in nails. The combination of a long swinging range, and heavy head, increase the force of the resulting impact.
Sledgehammers are often used in destruction work, for breaking through drywall or masonry walls. Sledgehammers are seldom used in modern mining operations, particularly hand steel. Sledgehammers are also used when substantial force is necessary to dislodge a trapped object (often in farm or oil field work), or for fracturing concrete. Another common use is for driving fence posts into the ground. Sledgehammers are used by police forces in raids on property to gain entry by force, commonly through doors. They were and still are commonly used by blacksmiths to shape heavy sections of iron. The British SAS counter terrorist team used sledge hammers to gain access to rooms during the 1980 Iranian Embassy Siege. However, today they use a tool called a "dynamic hammer."
Sledgehammers are increasingly being used as inexpensive exercise equipment; since all major upper body muscle groups need to put forth a significant amount of force when swinging a sledgehammer, it can easily be used to work muscles to failure as in resistance training. A tire is often used as the hammer's target as its elasticity reduces the shock to the user's joints when used for this purpose.
Another iconic use of sledgehammers is for driving railroad spikes into wooden sleepers during rail construction. When the two ends of the Union Pacific railroad were joined at Promontory, Utah, Leland Stanford hammered a golden spike into a tie with a silver hammer. Sledges used to drive spikes for rails had a curved head that came down to a "beak" that was only about 1 inch across. The shape meant that drivers needed to be accurate, and spot where the spike hit was often not much larger than a dime. Anything larger would hit the plate or the tie. They look awkward to use, but practice makes it easier, like hitting a baseball. The curved head kept the handle away from the rail, as the spikes were driven with the rail between the spike and the driver (if you consider the angle, you will see it has to be that way. The spike is driven in at an angle aimed at rail, so the head would catch the rail.)
In China 
A common sledgehammer design in China uses an extremely long handle that is very flexible. This may be made of fiberglass, special tubing (see image), or strips of bamboo stacked together and bound, which functions like a leaf spring. The advantages of this design are the increased velocity with which the operator can strike the target, and reduced jarring.
Post maul 
Post mauls are similar to sledgehammers in shape, but are meant to drive wooden fence posts or tree stakes into the earth. They have broad, flat circular faces that are significantly larger in diameter than the body of the head (where the handle attaches). Sledgehammers usually have octagonal faces that are the same diameter or slightly smaller than the body of the head.
See also 
- An Anglo Saxon Dictionary, Joseph Bosworth, The Clarendon press, 1882
- "Slag". Online Etymology Dictionary. Retrieved 27 June 2012.
- Richards, Robert (1908). Ore Dressing. New York, New York: McGraw-Hill Book Company. p. 10.
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