The reeded edge of a coin in the grooved lines encircles some U.S. coins' perimeter, such as the dime, quarter, and half dollar. If you inspect other coins, you will see that some of them don't have any reeding on the edge of the coin. You may also find coins with words or symbols on edge. Regardless of what adorns the edge of a coin, it's there for a purpose.
How Do the Reeds Get on the Edge of the Coin?
Those small grooves that you find on the edge of a coin are usually added during the striking process. Coin dies produce the obverse and the reverse of the coin. To hold the coin securely during the striking process, a metal collar that is the exact diameter of the finished coin is placed in between the two coin dies. At the United States Mint, the collar is only 1/5000 of an inch wider than the diameter of the coin die. This very tight tolerance forces the metal during the strike into the deepest recesses of the coin die instead of squishing out the side. A planchet is placed on top of the anvil die and held securely by the collar.
The collar has a series of small grooves carved into it around the entire circumference. When the planchet is struck at enormous pressure, the metal in the coin tries to expand out the side but is held in place by the collar. The tiny grooves on the collar are now transferred to the edge of the coin.
Another method used to impart reeding and other edge adornments is to strike the coin first and then put it through a milling machine which will add the reeds or different designs to the edge of the coin. This process is ordinarily done by rolling and squeezing the coin in between two metal strips that have the grooves or other designs engraved on them. The Presidential dollar series coins produced for circulation use this method for imparting the incuse edge lettering on the coin. This method of adding the edge adornments after the coin has been struck has led to numerous error coins being released into circulation.
Why Do They Put Reeds on the Edge of a Coin?
Originally, minting facilities made coins from precious metals such as gold and silver. As coins circulated, unscrupulous people would use a knife or file to scrape off a little bit of metal from each coin they handled. As hundreds or even thousands of people shaved off a small amount of precious metal, the coin would get smaller and be worth less than its stated value.
In colonial times, merchants weighed the coins people used to purchase goods. If they were underweight, the merchant would ask for additional coins to make up the difference. Unfortunately, some unscrupulous merchants used scales that were out of balance so that the weighed coins would always be shown as underweight. This way, the merchant could get more money for the goods he was selling.
To stop this practice of shaving or "clipping" coins, mints around the world added adornments such as reeds, lettering, or other decorative devices. If the edge adornments were gone, then you knew someone had clipped the coin and reduced the amount of precious metal in the coin.
What Are Other Types of Edges on Coins?
Although there is no definitive list of the different types of edges on coins, here are a few of the most common (and some uncommon) edges you will find on coins from around the world:
- Plain: The edge is smooth with no indentations or design on it.
- Reeded: A series of tiny grooves running perpendicular that encompass the entire edge of the coin.
- Lettered: Letters can be relief or incuse into the coin's edge. They may contain complete words, abbreviations, and/or symbols.
- Grooved: This edge contains a groove that runs parallel to the surface of the coin and circumnavigates the entire edge of the coin. At first glance, this may look like two coins glued together.
- Interrupted Reeded: A series of reeds followed by an equal space of plane or unadorned edge. This pattern repeats on the entire edge of the coin.
- Indented: A series of indentations equally spaced around the coin's edge. This is found on some euro coins, like the 20-cent euro.
- Herringbone: A series of crisscrossed tiny grooves that form a shape that resembles interconnected arrows and encompass the entire edge of the coin.
- Serrated: A series of grooves forming a V shape on the coin's edge. It continues evenly around the entire circumference of the coin.
- Slant Reeded: A series of grooves slanted across the edge of the coin. Very similar to reeded edges, but the grooves are slanted. This type of reading cannot be applied to the coin during the striking process.
- Center Reeded: These grooves on the edge of the coin do not extend completely across the coin's edge. They are limited to the center of the edge. This is another example of an edge of adornment that must be applied after the coin is struck.
Edited by: James Bucki