Hi all, Every now and then I see as part of a NGC attribution the words WHEEL MARK I guess it's bad enough for them to give this designation.. for me they are annoying! Here is their definition - Quote - "Wheel marks are a concentrated area of hairlines that are caused by the rubber wheels in coin counting machines. When there is insufficient spacing between them, the wheels can essentially polish a small portion of the surface of the coin." closed quote I want to share this webpage with you - https://www.ngccoin.com/news/article/4412/Wheel-Marks/ Here are my Error "WHEEL MARK" coins from my collection
Wheel marks are very easily overlooked, even victimizing dealers sometimes. It's far easier to show someone in person, but I'll try to describe how to detect them in words . . . a difficult task , at best. Give me a few minutes, and I'll try to come up with something in a subsequent post. - Mike
Here's the best I can do in writing . . . Because of their fineness, and perfectly parallel orientation, the wheel marks usually are apparent only from two opposite vantage points, both 90 degrees to the lines, and at shallow viewing angles. Be sure to rotate the coin completely around all 360 degrees of arc to make sure you are not missing wheel marks that may be there, as they can be extremely difficult to detect. - Mike
TC, I've been told that it is easier to spot wheel marks by examining the coin under a halogen lamp. Is that true? Chris
Sorry Paddy, I accidentally wrote "extremely difficult to overlook" and have since edited to "extremely difficult to detect". I wish they were difficult to overlook. I think that would make everyone happier.
I wonder if there are certain types of errors, like the ones you posted, that are more prone to having wheel marks? Chris
Error coins seem to be prone to these marks due to the often irregularity of the error's shape. "Wheel marks" are generally due to the counting wheels but they can be made when any rotating wheel comes into contact with the coin's surface. Much of the time (easiest to detect) they leave a bright PL patch on the coin that is especially visible when the coin is held in certain orientations to the light (mentioned above). The most deceptive wheel marks are usually found on frosty Unc Washington quarters, dimes, and Half dollars. On these, the patch is more like a series of parallel hairlines that blend in with the surface. Although often caused by a "wheel" of some sort they don't meet the criteria. When they are present, coins that look like gems are just downgraded as most collectors cannot detect them at all and the coins look nice.
There's an article on NGC with very good picture examples: (https://www.ngccoin.com/news/article/4412/Wheel-Marks/)
I'll need to try that. Cannot imagine (?) anyone at a coin show or dark grading room walking outside to look at a coin in the sunshine. Hope it isn't a rainy day...LOL.
