1 Archaeologists have now discovered the first appearance of a tool used as a hammer was 3.3 million years ago (found in Lake Turkana in northern Kenya in 2015) when a “hammer stone” was used to splinter more brittle stones like flint, into cutting and killing tools. After they began to perfect their technique, they formed and shaped axes, knives, then more intricate arrow heads and spear heads. Still later these proto-humans used the formed shards into carving tools for wood, to break open animal skulls, bones, shells and even make jewellery.

hammer (n.)
2 Old English hamor "hammer," from Proto-Germanic *hamaraz (source also of Old Saxon hamur, Middle Dutch, Dutch hamer, Old High German hamar, German Hammer). The Old Norse cognate hamarr meant "stone, crag" (it's common in English place names), and suggests an original sense of the Germanic words as "tool with a stone head," which would describe the first hammers. The Germanic words thus could be from a PIE *ka-mer-, with reversal of initial sounds, from PIE *akmen "stone, sharp stone used as a tool" (source also of Old Church Slavonic kamy, Russian kameni "stone"), from root *ak- "be sharp, rise (out) to a point, pierce."

As a part of a firearm, 1580s; as a part of a piano, 1774; as a small bone of the ear, 1610s. Figurative use of "aggressive and destructive foe" is late 14c., from similar use of French martel, Latin malleus. To go at it hammer and tongs "with great violence and vigor" (1708) is an image from blacksmithing (the tongs hold the metal and the hammer beats it). Hammer and sickle as an emblem of Soviet communism attested from 1921, symbolizing industrial and agricultural labor.

hammer (v.)
late 14c., "deal blows with a hammer or axe;" mid-15c., "to produce (something) by blows with a hammer," from hammer (n.). Also sometimes in Middle English the verb to describe how Christ was crucified. Figurative meaning "work (something) out laboriously" recorded from 1580s. Meaning "beat or drive with or as if with a hammer" is from 1640s; that of "to defeat heavily" is from 1948. Old English had hamorian "to beat out, forge." Related: Hammered; hammering.

English:

2 This embryonic hammer, was little more than a heavy elliptical stone between 300 grams to a kilo smoothly formed at the bottom of a river bed, or from the sea. The stone was used to hit an object, which was sitting on a large flat stone below it, like an anvil. If a more intricate point was needed, the stone hammer would be replaced with a smaller stone, bones, ivory and antlers using more finesse for finishing the new cutting tools.

3 The use of simple hammers dates to around 3.3 million years ago according to the 2012 find made by Sonia Harmand and Jason Lewis of Stony Brook University, who while excavating a site near Kenya's Lake Turkana discovered a very large deposit of various shaped stones including those used to strike wood, bone, or other stones to break them apart and shape them. The first hammers were without handles. Later stones attached to sticks with strips of leather or animal sinew were being used as hammers with handles by about 30,000 BCE during the middle of the Paleolithic Stone Age. The addition of a handle gave the user better control abilities and less accidents. The hammer became the number one tool. Used for building, food and protection.
The hammer's archeological record shows that it may be the oldest tool for which definite evidence exists of its early existence.

• Claw
  

  Estwing claw hammer
  - The claw hammer is the type of hammer generally used by carpenters and woodworkers. The peen of this hammer is bent and shaped so that it can be used for pulling nails. The face of the hammer often is slightly convex, or bell-faced, so that it will not make a circular mark on the surface of the wood after striking the last blow on the head of a nail. It is important to keep the face of the hammer clean and free from grease or glue, so that it will not glance off the head of a nail and bend it. The size of the hammer is indicated by the weight of the head in pounds and ounces.
• Ball Pein
  

  Buck Knives ball pein hammer
  - A ball-pein hammer, also known as a machinist's hammer, is a type of peening hammer used in metalworking. It is distinguished from a cross-peen hammer, diagonal-peen hammer, point-peen hammer, or chisel-peen hammer by having a hemispherical head. It is commonly used as a tool for metalworking.
• Cross and Straight Pein -
• Club -
• Sledge - 4 A sledgehammer is a tool with a large, flat, often metal head, attached to a long handle. The long handle combined with a heavy head allows the sledgehammer to gather momentum during a swing and apply a large force compared to hammers designed to drive nails.
• Joiner's Mallet - Mallets are wooden hammers. As wood is more elastic than iron or steel, a mallet should always be used when driving on wood. The blows of a steel hammer would soon splinter a chisel handle and mar a joint to be driven together beyond repair.
• Soft-faced -

Striking another object for the purpose of forcing into place that object. The hammer is used to drive nails into wood, also for carving by striking a chisel on the end of the handle to force the cutting edge of the chisel into the wood.

A hammer is a handheld tool used to strike another object. It consists of a handle to which is attached a heavy head, usually made of metal, with one or more striking surfaces. There are dozens of different types of hammers. The most common is a claw hammer, which is used to drive and pull nails.

• Hammer Museum
• Tool Blogger (History of the Hammer)

• Hjorth, Herman (Principles of woodworking ) 1930 (The Bruce Publishing Company) Milwaukee, Wis