Double strike (coin)
The double strike (French: tréflage ) is a minting error in the manufacture of coins . A double strike occurred quite often during hammer minting : If the upper die is struck twice or even several times on the coin blank , there may be a shift between the blank and the die. A subsequent hammer blow then stamps an image of the stamp that is shifted from the first blow into the coin. Often parts of the first embossing process are retained. The coin then shows two coin images shifted against each other. This phenomenon is known as a double strike.
With multiple strokes, multiple shifts of the coin images occur. If the coin blanks are not of the same thickness everywhere or if the die is not positioned exactly vertically, the double impact may only appear on part of the coin image. Not only can there be repetition here, but parts of the design can also be missing. Especially when parts of the inscription on the coins are affected (e.g. years in Roman numerals), double strikes can lead to difficulties in the numismatic examination of the coin.
Multiple strikes were regularly planned for larger coins (medieval groschen minting , multiple thalers such as the Braunschweiger solver ) or for coins with particularly deep relief (e.g. Syracuse decadrachms). Even with small coins, a second strike was carried out if the first was not sufficient for a sufficient minting. Of course, an attempt was made to avoid a double strike that would disturb the coin image.
Minting with the pusher and other minting machines has greatly reduced the need for multiple “blows”, even for large coins. Especially since the introduction of the ring coinage, even multiple coining hardly leads to a double strike, as the coin is well fixed in relation to the upper and lower stamp.
literature
- Friedrich v. Schrötter (Hrsg.): Dictionary of coinage . de Gruyter, 2nd unchanged. Edition, Berlin 1970 (reprint of the original edition from 1930). Article Doppelschlag , p. 146.