A punch is a hard metal

Metal

A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...

 rod with a shaped tip at one end and a blunt butt end at the other, which is usually struck by a 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,...

. Punches are used to drive objects, such as nail

Nail

Nail may refer to:* Nail , toughened keratin at the end of an animal digit* Nail , a plate of hard horny tissue at the tip of some bird beaks* Nail , the pin-shaped fastener used in engineering, woodworking and construction...

s, or to form an impression of the tip on a workpiece. Decorative punches may also be used to create a pattern or even form an image.

Nail or pin

A nail punch, also called a nail set, is used to drive the head of a nail flush with or below a surface. A pin punch is a similar tool used to drive pins for affixing a fixture to a rotating shaft. Nail and pin punches have a body by which the punch is held, with a flat ended cylindrical section whose diameter suits the object to be driven.

Center

A center punch is used to mark the center of a point. It is usually used to mark the center of a hole when drilling

Drilling

Drilling is a cutting process that uses a drill bit to cut or enlarge a hole in solid materials. The drill bit is a multipoint, end cutting tool...

 holes. A drill bit

Drill bit

Drill bits are cutting tools used to create cylindrical holes. Bits are held in a tool called a drill, which rotates them and provides torque and axial force to create the hole. Specialized bits are also available for non-cylindrical-shaped holes....

 has the tendency to "wander" if it does not start in a recess. A center punch forms a large enough dimple to "guide" the tip of the drill bit. When drilling larger holes, and the web of the drill is wider than the indentation produced by a center punch, the drilling of a pilot hole

Pilot hole

A pilot hole is a smaller hole drilled into a material prior to a larger hole being drilled, widening the hole to the desired width. Drilling a pilot hole prevents a larger drill bit from slipping on the material - a potential safety hazard, as well as an increased likelihood of the work being...

 is usually needed.

An automatic center punch

Automatic center punch

An automatic center punch is a hand tool used to produce a dimple in a workpiece . It performs the same function as an ordinary center punch but without the need for a hammer...

 operates without the need for a hammer.

Prick

A prick punch is similar to a center punch but used for marking out

Marking out

Marking out or layout is the process of transferring a design or pattern to a workpiece, as the first step in the manufacturing process...

. It has a sharper angled tip to produce a narrower and deeper point. The mark can then be enlarged with a center punch for drilling.

Transfer

A transfer punch is a punch (usually in an index set

Index set

In mathematics, the elements of a set A may be indexed or labeled by means of a set J that is on that account called an index set...

) of a specific outer diameter that is non-tapered and extends the entire length of the punch (except for the tip). It is used to tightly fit the tolerances of an existing hole and, when struck, precisely transfer the center of that hole to another surface. It can be used, for example, to duplicate the hole patterns in a part, or precisely set locations for threaded holes (created by drilling and tapping

Taps and dies

Taps and dies are cutting tools used to create screw threads, which is called threading. A tap is used to cut the female portion of the mating pair . A die is used to cut the male portion of the mating pair . The process of cutting threads using a tap is called tapping, whereas the process using a...

) to bolt an object to a surface.

Doming

A doming punch is used in conjunction with a doming block to make spheres or hemispheres out of sheets of metal. The punch is generally made of tool steel

Tool steel

Tool steel refers to a variety of carbon and alloy steels that are particularly well-suited to be made into tools. Their suitability comes from their distinctive hardness, resistance to abrasion, their ability to hold a cutting edge, and/or their resistance to deformation at elevated temperatures...

, but can be made of wood. They come in a number of different sizes, the punch size determining what size the finished product will be.

Drift

A drift "punch" is misleadingly named; it is not used as a punch in the traditional sense of the term. A drift punch, or drift pin, is used as an aid in aligning bolt or rivet

Rivet

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...

 holes prior to inserting a fastener. A drift punch is constructed as a tapered rod, with the hammer acting on the large end of the taper. The tapered end of a drift punch is placed into the semi-aligned bolt holes of two separate components, and then driven into the hole. As it is driven in, the taper forces the two components into alignment, allowing for easy insertion of the fastener. Unlike most punches, force is never (and should never be) applied to the tip, or end of a drift pin.

Decorative

Punches with a decorative motif have been used to create patterns or images on metals and various other materials, notably leather

Leather

Leather is a durable and flexible material created via the tanning of putrescible animal rawhide and skin, primarily cattlehide. It can be produced through different manufacturing processes, ranging from cottage industry to heavy industry.-Forms:...

. In goldsmith

Goldsmith

A goldsmith is a metalworker who specializes in working with gold and other precious metals. Since ancient times the techniques of a goldsmith have evolved very little in order to produce items of jewelry of quality standards. In modern times actual goldsmiths are rare...

ing, bookbinding

Bookbinding

Bookbinding is the process of physically assembling a book from a number of folded or unfolded sheets of paper or other material. It usually involves attaching covers to the resulting text-block.-Origins of the book:...

 and armour

Armour

Armour or armor is protective covering used to prevent damage from being inflicted to an object, individual or a vehicle through use of direct contact weapons or projectiles, usually during combat, or from damage caused by a potentially dangerous environment or action...

-making the technique is called pointillé

Pointillé

Pointillé is a decorative technique in which patterns are formed on a surface by a means of punched dots. The technique is similar to embossing or engraving but is done manually and does not cut into the surface being decorated. Pointillé was commonly used to decorate arms and armor starting in...

. In printmaking

Printmaking

Printmaking is the process of making artworks by printing, normally on paper. Printmaking normally covers only the process of creating prints with an element of originality, rather than just being a photographic reproduction of a painting. Except in the case of monotyping, the process is capable...

 punches were used to create most of the image in the plates for printing metalcut

Metalcut

Metalcut is a relief printmaking technique, belonging to the category of old master prints. It was almost entirely restricted to the period from about 1450 to 1540, and mostly to the region around the Rhine in Northern Europe, the Low Countries, Germany, France and Switzerland; the technique...

s.

Letter

Also known as letter stamps or number stamps. These are used to emboss the impression of a letter or number into a workpiece. They are most common in the reverse image

Mirror writing

Mirror writing is formed by writing in the direction that is the reverse of the natural way for a given language, such that the result is the mirror image of normal writing: it appears normal when it is reflected in a mirror. It is sometimes used as an extremely primitive form of cipher...

, this allows the end result to be immediately readable, however they may be made as a positive image. This is essential in the case of die or mold

Molding (process)

Molding or moulding is the process of manufacturing by shaping pliable raw material using a rigid frame or model called a pattern....

 making and ensures that the finished product will be readable, as a die is a negative image.

Tablet press

These punches are a part of tablet press

Tablet press

A tablet press is a mechanical device that compresses powder into tablets of uniform size and weight. A press can be used to manufacture tablets of a wide variety of materials, including pharmaceuticals, illicit drugs such as MDMA, cleaning products, and cosmetics...

. Unlike most punches, tablet press punches have a concave ending in the shape of the desired tablet

Tablet

A tablet is a pharmaceutical dosage form. It comprises a mixture of active substances and excipients, usually in powder form, pressed or compacted from a powder into a solid dose...

. There are the lower and the upper punches to compress the powder in between.