1999P Connecticut State Quarter with DD

[Francis]

Are CHAR and 88 in the attached photos DD?

[onecent1909]

No this is Machine doubling. when a die bounces on a struck coin and smashes down a coins design.

[MintErrors]

It's a lot lower and shelf like. The doubled dies are impressed into the working dies at the same pressure or depth, so the area in question should be at nearly the same height.

Another good practice is to visit http://varietyvista.com to see if there are any very close matches. Remember, with these doubled dies impressed into metal working dies, they do no move locations. The atrributors typically show the locations where the double die is relatively apparent.

[Francis]

Amazing! In a fraction of a second, the die strikes the penchant twice and even produces an image which looks different from the designed features in the die. Could scientists simulate this process based on physical laws?

[MintErrors]

In my opinion, it happens a lot more than most people want to admit. It's a Machine flaw, introduced by human error during the set up, or a condition that induced this issue.

In current day, you will easily find worthless doubling like this a lot. I venture to guess, in today's coin era, you will see 100 to 1000 worthless doubling before you find one doubled die roll hunting.

One has to realize how quickly these machines operate. Research the year and mintmark. Take the total amount of quarters produced for that year and divide it by 340 or so days, then by hours and minutes, then to seconds. They typically use 9 to 15 machines to make coins, and they operate at jackhammer speeds.

There were 688,744,000 quarters minted in Philadelphia for this coin. If my math is right and they ran an average of 9 machines 340 days, 24 hrs a day, they would need to have the machines strike almost 3 planchets into coins in a second, per machine.

[Francis]

It does not matter with me, if a coin with machined doubling marks has no value in the market. I would still collect them, for they are unique and quite interesting.