Help Me Figure Out The Nuances Of What Makes A Penny Rare

What he was probably talking about is training your eye to distinguish a normal coin, a machine damaged coin and a coin that exhibits hub doubling. During the years of 1968-1972 there were a lot of machine damaged devices on coins. These are often called "machine doubled-mechanical doubled-strike doubled-studder strikes" because they are caused by die movement during the strike. This movement of the dies damages the coins devices and some refer to it as doubling. I refer to it as what it really is, damage to the devices. This MD is actually reducing the size of the devices. Most of the time it occurs partly up the device. So you see the damage at the upper part of the devices. Probably the greatest example I could show you is this coin:

Note the area where the die disturbed the normal shape of this device? Training your eye to distinguish this is part of the learning process on coins. Because of the "Big" doubled die for this year, many look hard to find this coin. Very few are known. So when they find a 1969-S that is the first thing they look for. Here are a few examples of this hub doubling seen on these coins:

Notice the extra thickness of the devices on the motto?
Here is a closer view of the date:

Sometimes the MD can happen even on a hub doubled example:

Note how the bottom image shows on the arrows where the MD reduced the size of the devices?
So what is the difference? On MD the die is normal and the die movement pushed into the devices damaging them. These are to me, a damaged coin. Because of the higher percentages of this happening on these years, to me it is something I don't want. But if I found a 1969-S Big DDO (Doubled-Die-Obverse) then I would be a very happy camper. There are probably less than 100 known. So a lot of collectors want to find this coin. It is very desirable. But how down you know one from the other? By training your eye to post them. Here are a few examples of MD to help you see the difference:


Another difference is the value for a hub doubled coin and a MD coin. To me a MD coin is just worth face value. I save them only for educational purposes. But hub doubling on a coin would be worth thousands. Here is an example:






So knowing which is which involves training your eye.
Hope this helps.

For more information you might check out my youtube videos 1-5 in my signature line.

Low mintage will often make a cent rare. For example the 1909-S VDB has a mintage of only 475,000 while the more abundant 2000 Lincoln Cent has a mintage of 5,503,200,000. Errors and varieties also make coins collectable. Here is an online error guide that may help you with that part: http://www.lincolncentsonline.com/error.html

Good images! I have a hard time getting good images like this.
I Love the older coins. They're so fascinating.

Take them one coin at a time. You might see the same things happening on different coins. So when you get closer images, make a new thread for each coin. Take your time It is a learning experience. So best to know why, rather than yes or no. That is the way I teach.

Interesting. Thanks to coop and cwb.