Machine Damage Or Hub Doubling How To Tell The Difference

Often we run into machine damage on coins. this reduces the upper parts above the fields near the base or above the lower part of the fields. This can happen near the base of the devices, or in the upper 1/3 or 1/2 of the device.


This happens after the strike happens, then movement or bounce from the machine will alter the device, damaging an area/areas on the coin. This is a striking issue. New collectors often see this and think it is a doubled die. The chances of find a true doubled die are rare in circulation coins. But the chances of finding MD is a lot easier.

But what is the difference between the two. Machine damage can happened on a normal die or even a doubled die. What?

Note the normal strike, but look at the arrows on the lower image.

The normal dies is often the ones we find the MD on, but this can occur on a doubled die as well? How? They are exactly the same to the machine. The die movement during the strike can altered either types of dies.

On a doubled die, the doubling is on the die. It was hubbed incorrectly. There are 9 classes of doubled dies that are the ways hub doubling can happen. But the doubling on a doubled die is on the die thus the term doubled die On a machine damaged coin the machine causes the damage on the coins. It is not a die issue, but a machine issue. The damage is caused before the coin leaves the machine. But this is a common event. Examples are often found. If the mechanism is loose, you can see it on several examples in the same run of this machine. They will be different from strike to strike.

Note the marker on the coins are all the same, but the machine damage is different from strike to strike. These were found in original bank wrapped rolls from the past from the same run.

Often the machine damage is near the bottom of the base, but it always reduces the size of the devices.



Hub doubling increases the size of the devices.


Note the differences in size of the doubled die devices compare with a normal one.





Keep in mind that there are varying degrees of hub doubling. Some stronger, others minor. It is often helpful if you have a roll of the new coins you look at different sites for listing of known doubled dies and other varieties to see what could be out there. Note the areas affected and use that in your searching.

Hope this helps in your search for non MD examples. Knowledge is power. But when it doubt, ask a question here. We are always here to help.