Last night my third and final eBay auction for my Washington $1 coin errors ended. The last coin was a rotated die error, meaning that the reverse design was struck rotated from where it should have been. I received this question through the eBay interface from an interested collector:
Hi, I am new to coin collecting and have a question. I have tons of the Washington coins. I would like to look for this error in my coins that you have found. My question is how do I tell if the die is rotated? Do you line it up somehow from the front of the coin or do you line up with mint marks? Or how do you look for this? I need to know so when I look through the thousands of these coins I have, I look for this error the right way. Thanks for your help.
I told him that this was an excellent question and that I'd try to answer it over here.
How I did it was actually pretty easy, and I could go through maybe 7 coins per minute. I took the coins one at a time, turned them face up in my hand, and flipped the coin over from top to bottom. (If you are looking for an “axis of rotation” it's a horizontal line through the center of the coin.) If, after doing this flip, the reverse design is upright, the coin is properly struck. If the design is not upright — rotated, or even upside down — the coin is not properly struck and it's a “rotated die” error.
This is a very coarse way of checking for these errors, but after my colleague found one that was rotated almost 40 degrees, I figured the method would be good enough to catch the really big rotated die errors.
Another more exacting way is to “card” the coins so that the obverse design is aligned with the card (so that if you stand the card up, the coin design is straight up and down). Coin cards are two square cards with circular holes covered with a transparent cellophane material so that the “carded” coin can be inspected without risk of touching the surface. The coin is sandwiched in between the two cards. Flipping the coin top to bottom is a little more controlled in the card, so it's possible to check for smaller rotations. (On the Presidential $1 coins, the “$1” on the back should be straight up and down on a properly struck coin if it's flipped over as I've described.) You can re-use the cards by fastening them together with paper clips instead of staples or tape.
Hope that this answers your question! Best wishes as you sort through your coins!
