A coin die is one of the two metallic pieces that are used to strike one side of a coin. A die contains an incuse version of the image to be struck on the coin. To imagine what the incuse version looks like, press a coin into clay or wax and look at the resulting inverted image. Modern dies made out of hardened steel are capable of producing many hundreds of thousands of coins before they are retired and defaced. 1¢ euro coin A coin is usually a piece of hard material, generally metal and usually in the shape of a disc, which is used as a form of money. ... Clay is a generic term for an aggregate of hydrous silicate particles less than 4 μm (micrometres) in diameter. ... Wax has traditionally referred to a substance that is secreted by bees (beeswax) and used by them in constructing their honeycombs. ... The old steel cable of a colliery winding tower Steel is a metal alloy whose major component is iron, with carbon being the primary alloying material. ...

Prior to the modern era, coin dies were manufactured individually by hand by artisans known as celators. In demanding times, such as the Crisis of the Third Century, dies were still used even when they became very worn or even when they cracked. The die that was on the anvil side, usually the reverse (back), tended to wear out first. Since the metals that the dies were made out of weren't as hard as modern steel, the flans (the blank pieces of metal), needed to be heated prior to striking. On some Roman provincial coins, the tongs used to move the heated flan sometimed left permanent center indentations on the finished coins. Crisis of the Third Century (also known as the Military Anarchy or the Imperial Crisis ) is a commonly applied name for the crumbling and near collapse of the Roman Empire between 235 and 284 caused by the three simultaneous crises of external invasion, internal civil war and economic collapse. ... Flan with Dulce de Leche and milk cream In cooking, flan is a custard-like dessert originating from Spain and is popular in former Spanish colonies such as Latin America, the Philippines, Puerto Rico, and Dominican Republic. ...

Modern die production

The process of making dies to strike coins in today's mint has quite a few steps. First, an artist creates a large plaster model of the coin. The plaster model is then coated with rubber. The rubber mold is then used to make an epoxy galvano. All of this takes place on a scale of around eight inches. Next, a Janvier reducing lathe takes several days to reduce the image onto a steel master hub in a process that has not changed in over a hundred years. The master hub is then tempered to make it hard. A small number of master dies (incuse) are then made from the master hub. These are then used to make working hubs. The working hubs are then used to make working dies. With each step, the number goes up. The working dies are then used to strike coins. All dies are incuse, and all hubs look like the coin being struck (with the devices raised.) This article is about the building material. ... Rubber is an elastic hydrocarbon polymer which occurs as a milky emulsion (known as latex) in the sap of a number of plants but can also be produced synthetically. ... Epoxy or polyepoxide is a thermosetting epoxide polymer that cures when mixed with a catalyzing agent or hardener. Most common epoxy resins are produced from a reaction between epichlorohydrin and bisphenol-A. The first commercial attempts to prepare resins from epichlorohydrin occurred in 1927 in the United States. ...

The final step of course is that the dies are used to strike images onto the planchet so that it becomes a coin. A planchet is a round metal disk that is ready to be struck as a coin. ...

Of course, mistakes can happen at any stage of this manufacturing process, and these mistakes are something that certain collectors look for. Coin errors that occur on the die are generally more desirable than errors made at the time of the strike. For example, a doubled die, where a date or another device appears twice slightly offset, is often a highly desired error. Strike errors are generally unique, whereas all coins struck with an error die will have the same characteristic. This makes them more easily collectible. The most famous doubled die in the past hundred years is the 1955 double die Lincoln cent. These trade for hundreds of dollars because the error can easily be seen by a casual observer. Many doubled die errors require at least a jeweler's loop (if not a healthy imagination) to be seen. Doubling can occur at the hub stage as well. Some more recent errors are hub doubled. Most famously, there is a 1995 doubled die cent that is hub doubled. The 1955 doubled die is a minting error that occurred during production of the one cent coin at the United States Mint, in 1955. ...

Since coin production in the United States has exceeded 20 billion coins in some recent years, this means that a lot of dies must be manufactured as well.

The Third Side of the Coin

On the edge of the US dime, quarter and half dollar, and many world coins there are ridges, similar to knurling, called reeds. Some older US coins, and many world coins have other designs on the edge of the coin. Sometimes these are simple designs like vines, more complex bar patterns or perhaps a phrase. These kinds of designs are imparted into the coin through a third die called a collar. The collar is the final size of the coin, and the planchet expands to fill the collar when struck. When the collar is missing, it results in a type of error called a broadstrike. A broadstruck coin is generally a bit flatter and quite a bit bigger around than the regular non-error coin of the same denomination. Two examples of the use of knurling in hand tools. ... A planchet is a round metal disk that is ready to be struck as a coin. ...

External link

• How coin are designed The creation of a die and the minting process
• US Treasury: Preparation of Working Dies
• How ancient dies were made.

WikiProject Metalworking:
Metal forming: Image File history File links Blacksmith-hammer-anvil-50x50. ... Metalworking is the craft and practice of working with metals to create parts or structures. ...	Coin die | Coining | Cold rolling | Die | Drawing | Electromagnetic forming | Flypress | Hot rolling | Hydraulic press | Hydroforming | Machine press | Punching | Punch press | Rolling | Shear | Swage Coining is a form of precision stamping. ... Rolling mill for cold rolling metal sheet like this piece of brass sheet. ... See Die for other meanings of this word A die is a tool used in the manufacture of parts by the molding process. ... Drawing is a manufacturing process for producing a wire, bar or tube by pulling on a material until it increases in length. ... Electromagnetic forming (EM forming) is a high energy rate metal forming process, that uses ultrastrong pulsed magnetic fields, to reshape metal parts rapidly . ... A Flypress is a metalworking machine tool used to punch holes in sheet metal in one operation, rather than by cutting the hole or drilling, etc. ... Hot rolling is a metallurgical process in which the metal is passed through a pair of rolls and the temperature of the metal is above its recrystallization temperature. ... The hydraulic press is a class of machine tool that was important in making possible the Industrial Revolution. ... Hydroforming is a cost-effective way of shaping malleable metals such as aluminum in to lightweight, structurally stiff and strong pieces. ... A press, or a machine press is a tool used to shape metal (typically steel) by bending it. ... Punching in metal fabrication is the process of using a machine to press a shape through a sheet of metal and into a die to create that shape in the metal. ... A Punch Press is a machine that has a set of punches and dies, a male (punch) and female (die), which when pressed together put a hole into the material used that is the same geometry as the punch that is being used. ... Rolling is a fabricating process in which the metal, plastic, paper, glass, etc. ... In physics and mechanics, shear refers to a deformation that causes parallel surfaces to slide past one another (as opposed to compression and tension, which cause parallel surfaces to move towards or away from one another). ... Swaging is a metal forming technique in which the metal is plastically deformed to its final shape using high pressures. ...
Metalworking topics:   Casting | CNC | Cutting machines | Cutting tools | Drilling and threading | Fabrication | Finishing | Grinding | Jewelry | Lathes | Machining | Machine tooling | Measuring | Metalworking | Hand tools | Metallurgy | Milling | Occupations | Press tools | Smithing | Terminology | Welding Casting is a process by which a material is introduced into a mold while it is liquid, allowed to solidify in the shape inside the mold, and then removed producing a fabricated object, part, or casing. ... A CNC Turning Center The abbreviation CNC stands for Computer(ized) Numerical(ly) Control(led), and refers specifically to the computer control of machine tools for the purpose of (repeatedly) manufacturing complex parts in metal as well as other materials, using a program written in a notation conforming to the... Drilling is the process of using a drill bit in a drill to produce holes. ... A typical steel fabrication shop Fabrication is an industrial term generally applied to the building of metal machines and structures. ... Rotating abrasive wheel on a bench grinder. ... Jewelry (the American spelling; spelled jewellery in Commonwealth English) consists of ornamental devices worn by persons, typically made with gems and precious metals. ... This article is about a lathe as a tool. ... A lathe is a common tool used in machining. ... A machine tool is a powered mechanical device, typically used to fabricate metal components of machines by the selective removal of metal. ... Metalworking is the craft and practice of working with metals to create parts or structures. ... Metalworking hand tools are hand tools that are used in the metalworking field. ... Metallurgy is a domain of materials science and of materials engineering that studies the physical and chemical behavior of metallic elements and their mixtures, which are called alloys. ... A Milling machine is a power-driven machine used for the complex shaping of metal (or possibly other materials) parts. ... Power press with a fixed barrier guard A press, or a machine press is a tool used to work metal (typically steel) by changing its shape and internal structure. ... A smith or metalsmith is a person involved in the shaping of metal objects. ... Welding is a fabrication process that joins materials, usually metals or thermoplastics, by causing coalescence. ...