
Ball-peen hammer
Encyclopedia

Peening
Peening is the process of working a metal's surface to improve its material properties, usually by mechanical means such as hammer blows or by blasting with shot . Peening is normally a cold work process...
hammer
Hammer
A hammer is a tool meant to deliver an impact to an object. The most common uses are for driving nails, fitting parts, forging metal and breaking up objects. Hammers are often designed for a specific purpose, and vary widely in their shape and structure. The usual features are a handle and a head,...
used in metalworking
Metalworking
Metalworking is the process of working with metals to create individual parts, assemblies, or large scale structures. The term covers a wide range of work from large ships and bridges to precise engine parts and delicate jewelry. It therefore includes a correspondingly wide range of skills,...
. It is distinguished from a point-peen hammer or chisel-peen hammer by having a hemispherical head. Though the process of peening has become rarer in metal fabrication, the ball-peen hammer remains useful for many tasks, such as striking punch
Punch (tool)
A punch is a hard metal rod with a shaped tip at one end and a blunt butt end at the other, which is usually struck by a hammer. Punches are used to drive objects, such as nails, or to form an impression of the tip on a workpiece...
es and chisel
Chisel
A chisel is a tool with a characteristically shaped cutting edge of blade on its end, for carving or cutting a hard material such as wood, stone, or metal. The handle and blade of some types of chisel are made of metal or wood with a sharp edge in it.In use, the chisel is forced into the material...
s.
Uses
The original function of the hammer was to peen rivetRivet
A rivet is a permanent mechanical fastener. Before being installed a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite the head is called the buck-tail. On installation the rivet is placed in a punched or pre-drilled hole, and the tail is upset, or bucked A rivet...
ed or welded
Welding
Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material that cools to become a strong joint, with pressure sometimes...
material, which makes it as flexible as the surrounding metal. Today, the ball end of the hammer is used to cut gasket
Gasket
thumb|sright|250px|Some seals and gaskets1. [[o-ring]]2. fiber [[Washer |washer]]3. paper gaskets4. [[cylinder head]] [[head gasket|gasket]]...
s, expand and shape the free end of copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
roves, light rivets, and "set" rivets (which completes the joint).
Variants
Variants include the straight-peen, diagonal-peen, and cross-peen hammer. These hammers have a wedge-shaped head instead of a ball-shaped head. This wedge shape spreads the metal perpendicular to the edge of the head. The straight-peen hammer has the wedge oriented parallel to the hammer's handle, while the cross-peen hammer's wedge is oriented perpendicular. The diagonal-peen hammer's head, as the name implies, is at a 45° angle from the handle. They are commonly used by blacksmithBlacksmith
A blacksmith is a person who creates objects from wrought iron or steel by forging the metal; that is, by using tools to hammer, bend, and cut...
s during the forging
Forging
Forging is a manufacturing process involving the shaping of metal using localized compressive forces. Forging is often classified according to the temperature at which it is performed: '"cold," "warm," or "hot" forging. Forged parts can range in weight from less than a kilogram to 580 metric tons...
process to deliver blows to a forging or strike other forging tool
Tool
A tool is a device that can be used to produce an item or achieve a task, but that is not consumed in the process. Informally the word is also used to describe a procedure or process with a specific purpose. Tools that are used in particular fields or activities may have different designations such...
s.
Head materials
Ball-peen hammers have two types of heads: hard-faced and soft-faced. The head of a hard-faced hammer is made of heat treated forgedForging
Forging is a manufacturing process involving the shaping of metal using localized compressive forces. Forging is often classified according to the temperature at which it is performed: '"cold," "warm," or "hot" forging. Forged parts can range in weight from less than a kilogram to 580 metric tons...
high-carbon steel or alloy steel; it is harder than the face of a claw hammer
Claw hammer
A claw hammer is a tool primarily used for pounding nails into, or extracting nails from, some other object. Generally, a claw hammer is associated with woodworking but is not limited to use with wood products...
. The soft-faced hammers are made from brass
Brass
Brass is an alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties.In comparison, bronze is principally an alloy of copper and tin...
, lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
, tightly wound rawhide, or plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
. These hammers usually have replaceable heads or faces, because they will deform, wear out, or break over time. They are used to prevent damage to a striking surface, and are graded by the weight of the head.