Die alignment, also called die axis or coin rotation, is expressed in degrees and describes how the obverse and reverse dies were aligned to each other when the coin was struck. Some publications use arrows to describe die alignment.
The best way to look at it is to put a straight edge on the face of the coin with the edge at the top (0 degrees) and the bottom (180 degrees) through the center. While holding the straight edge to the coin turn it over and note where the “top” of the reverse device is. If it is in the same place as the top of the front device it is called 0-degree alignment. If the top of the reverse is at the bottom it is called 180-degree alignment. Another way to examine die alignment is to hold the coin on the edge with the obverse facing you, your index finger at the top of the obverse design (0 degrees) and the thumb at the bottom of the design (180 degrees); then rotate the coin horizontally maintaining your index finger and thumb fixed on the same spot on the rim.
The 0-degree alignment is called Medallic Rotation, while the 180-degree alignment is called Coin Rotation. Now for the “real world”; Roman coinage was made using dies that were movable, so true 0 or 180 degree rotations were not always made. You must guess at the rotation, to the nearest 15 degrees, if it is not at the 0 or 180 degree mark. If you turn the coin over with the straight edge on it and the top of the obverse at the top of the rotated coin you must observe where the “top” of the reverse device is. If you observe that the top of the reverse device is pointing towards where the 3 would be on a clock face this is said to be 90-degree rotation. Or if it is pointing to the spot where the 9 would be on the face it is said to be 270-degree rotation.
Die alignment is useful in detecting older forgeries because the consistency of die alignment in some issues was not know centuries ago. Die alignment is much less useful in detecting modern forgeries because most forgers are now aware of this characteristic.
Some issues do not show any consistency or pattern in die alignment. These issues can be described as struck with "loose dies."
An alternative system is to use hours of the clock, (0 degrees = 12:00; 30 degrees = 1:00; 90 degrees = 3:00, 180 degrees = 6:00 and so on).
Article Credit
Sarathi | Guide4Income | Physics4u | Shastri | India
