@TommyType said:
I'm not sure I get the "wheel mark" diagnosis, either. That term seems far too specific for what could be a wipe with a cloth, or slide across a table, or a rub with a hand, or some other cleaning material. Not sure where or why we would assume it was a "wheel" (or mechanical) of any kind. (The Walker seems intentional cleaning, while the Washington looks like mishandling).
I'm not picking on you TT but this image backs up the "wheel mark" nomenclature I use for many of these PMD coins.
Posters have asked how I determine a "wheel" is used to mark the surface of many of these coins. This quarter is not original yet it looks like an MS-63-64 FH. It has been cleaned to hide the corrosion spot on the wing. Note the curved hairlines. This is a characteristic that most would call a "wipe." Well it is NOT! Try to produce a mark as this with a cloth or anything else. IMO, it is a very light WHEEL MARK from a rotating "tool" of some kind.
@TommyType said:
I'm not sure I get the "wheel mark" diagnosis, either. That term seems far too specific for what could be a wipe with a cloth, or slide across a table, or a rub with a hand, or some other cleaning material. Not sure where or why we would assume it was a "wheel" (or mechanical) of any kind. (The Walker seems intentional cleaning, while the Washington looks like mishandling).
I'm not picking on you TT but this image backs up the "wheel mark" nomenclature I use for many of these PMD coins.
Posters have asked how I determine a "wheel" is used to mark the surface of many of these coins. This quarter is not original yet it looks like an MS-63-64 FH. It has been cleaned to hide the corrosion spot on the wing. Note the curved hairlines. This is a characteristic that most would call a "wipe." Well it is NOT! Try to produce a mark as this with a cloth or anything else. IMO, it is a very light WHEEL MARK from a rotating "tool" of some kind.
Actually....THAT is what I think of as a wheel mark! Concentric circles, caused by sorting machines. (Is it really caused by a wheel? I don't know....)
That's not to say that the original coin in the post ISN'T caused by a wheel. (None of us were there, so we don't know). I just don't know of any machine that puts a "wheel" on the surface of the coin like that. And, more importantly, I think someone COULD cause the same scratches with a cloth and some light to moderate rubbing. (Again....none of us were there!)
Comes down to nomenclature....which I don't think harms us if we disagree on. More important, we agree that it's "bad", and diminishes (or destroys) the value of the coin.
@TommyType said: "That's not to say that the original coin in the post ISN'T caused by a wheel. (None of us were there, so we don't know). I just don't know of any machine that puts a "wheel" on the surface of the coin like that. And, more importantly, I think someone COULD cause the same scratches with a cloth and some light to moderate rubbing. (Again....none of us were there!). Comes down to nomenclature....which I don't think harms us if we disagree on. More important, we agree that it's "bad", and diminishes (or destroys) the value of the coin."
There are some things in numismatics that are obvious. I've only been on earth for a short time yet I can look at a coin from centuries before and tell you what was done to it without needing to be around when it happened.
When two people can see a coin in hand, it really does not matter so much what they call a characteristic they see on it. When they cannot see a coin, it helps to use the correct terminology. Unfortunately, the study of the characteristics we find on coins and assigning terms to describe them is only a few decades old. Bet you didn't know that at one time (pre 1973) the ANA defined "Whizzing" as CHEMICAL CLEANING.
Do coin sorters/counters not have a wheel that accelerates the coins out? This is my understanding of how the sorting/counting machines work. If a coin gets jammed or otherwise stuck under one of the wheels it will make a patch of dense parallel lines, almost burnishing that small portion of the coin. Am I mistaken here?
These concentric rings are produced by a lathe which shapes the cone-shaped face of the unfinished working die. The cone is supposed to be polished smooth before hubbing.
If polishing is omitted or inadequate, the surface will remain covered by concentric lathe marks which will not be erased by subsequent hubbing.
Counter Wheel Marks are very often seen on Mint Errors. Coins with such marks which at time are very mild do make it into graded holders. When you see a coin that looks Gem Unc at less than arms length in a MS62 holder Counter Wheel Marks very likely are the reason it NET graded.
To Err Is Human.... To Collect Err's Is Just Too Much Darn Tootin Fun!
@grip said:
These concentric rings are produced by a lathe which shapes the cone-shaped face of the unfinished working die. The cone is supposed to be polished smooth before hubbing.
If polishing is omitted or inadequate, the surface will remain covered by concentric lathe marks which will not be erased by subsequent hubbing.
So why did you ask? You could have educated all of us when you posted the image that had nothing to do with the subject of this discussion.
Comments
I'm not picking on you TT but this image backs up the "wheel mark" nomenclature I use for many of these PMD coins.
Posters have asked how I determine a "wheel" is used to mark the surface of many of these coins. This quarter is not original yet it looks like an MS-63-64 FH. It has been cleaned to hide the corrosion spot on the wing. Note the curved hairlines. This is a characteristic that most would call a "wipe." Well it is NOT! Try to produce a mark as this with a cloth or anything else.
IMO, it is a very light WHEEL MARK from a rotating "tool" of some kind.
Actually....THAT is what I think of as a wheel mark! Concentric circles, caused by sorting machines. (Is it really caused by a wheel? I don't know....)
That's not to say that the original coin in the post ISN'T caused by a wheel. (None of us were there, so we don't know). I just don't know of any machine that puts a "wheel" on the surface of the coin like that. And, more importantly, I think someone COULD cause the same scratches with a cloth and some light to moderate rubbing. (Again....none of us were there!)
Comes down to nomenclature....which I don't think harms us if we disagree on. More important, we agree that it's "bad", and diminishes (or destroys) the value of the coin.
@TommyType said: "That's not to say that the original coin in the post ISN'T caused by a wheel. (None of us were there, so we don't know). I just don't know of any machine that puts a "wheel" on the surface of the coin like that. And, more importantly, I think someone COULD cause the same scratches with a cloth and some light to moderate rubbing. (Again....none of us were there!). Comes down to nomenclature....which I don't think harms us if we disagree on. More important, we agree that it's "bad", and diminishes (or destroys) the value of the coin."
There are some things in numismatics that are obvious. I've only been on earth for a short time yet I can look at a coin from centuries before and tell you what was done to it without needing to be around when it happened.
When two people can see a coin in hand, it really does not matter so much what they call a characteristic they see on it. When they cannot see a coin, it helps to use the correct terminology. Unfortunately, the study of the characteristics we find on coins and assigning terms to describe them is only a few decades old. Bet you didn't know that at one time (pre 1973) the ANA defined "Whizzing" as CHEMICAL CLEANING.
Do coin sorters/counters not have a wheel that accelerates the coins out? This is my understanding of how the sorting/counting machines work. If a coin gets jammed or otherwise stuck under one of the wheels it will make a patch of dense parallel lines, almost burnishing that small portion of the coin. Am I mistaken here?
Collector, occasional seller
Lathe marks.?
What do you call these? What causes them?
Good question. Do you know?
YES. Why not take some guesses. What do you call these? What causes them?
These concentric rings are produced by a lathe which shapes the cone-shaped face of the unfinished working die. The cone is supposed to be polished smooth before hubbing.
If polishing is omitted or inadequate, the surface will remain covered by concentric lathe marks which will not be erased by subsequent hubbing.
Counter Wheel Marks are very often seen on Mint Errors. Coins with such marks which at time are very mild do make it into graded holders. When you see a coin that looks Gem Unc at less than arms length in a MS62 holder Counter Wheel Marks very likely are the reason it NET graded.
So why did you ask? You could have educated all of us when you posted the image
that had nothing to do with the subject of this discussion.
I didn't know till I looked it up. Google.:)
Excellent. That's a beautiful example you posted.