3pen1dm.jpg
dimeclose.jpg
Posted 04/27/2008 07:47 am
The surface bumps on the cent are caused by little bubbles under the plating. Remember that all cents from the middle of 1982 on are zinc planchets with a copper plating over them. It is common to see bumps on zinc cents now and then from trapped gas bubbles. Especially in the 80's. The extra rim you are referring to is also common. When coins are struck the 2 dies are installed in the press and are like 2 round rods coming together end to end. Sometimes the dies aren't perfectly in line with each other end to end. In other words, the dies are parallel to each other but the 2 circular ends are shifted apart and do not meet exactly together. The press operator can adjust the upper (hammer) die to correct the alignment. This misalignment is called a misaligned die or MAD error. To have a premium the misalignment must be off so much that some of the design is missing. Usually it is letters since that is what is around the rim. You can tell if it is a MAD if it is off center on one side but on center on the other. Off center on both sides is simply an off center strike and not a MAD. The other thing you asked about is the higher rim. Good eye. But unfortunately the ones you show also appear normal. If the striking pressure is adjusted too high when the dies come together metal can start to flow up the one side of the die. This is called a fin. One side of the coin will have a thin almost knife like edge that is a little higher than the rest of the coin. Hope this helps your roll searching. You are on the right track with your questions. Keep looking at your coins and ask some more.
