This is a rather interesting topic to me since I'm so new to coin collecting. Are there really no photos out there that show before and after shots of a coin that was minted from a particular planchet? It just seems that over the years these types of photos would be available.
If you ask me, it should matter if the mark was from before or after minting. It's still a mark I don't want on my coin.
So the old uncollared strikes never had any pressure? You really are better than this. Think about it. The "3 things" that trap the planchet and create the pressure are the obverse die, the reverse die and resistance of the planchet to expand and deform. In your example. if the pressure is lower in the planchet, then the die moves closer. Moving closer does two things. It increases the pressure and it makes the strike better. I am sorry my verbal skills are not any better, but I guarantee my logic is correct.
I'm going to link an article by Bill Fivaz about what is going on here, even Bill claims these anomalies should not alter the perception of how the coin should be viewed. http://www.coinpedia.com/Errors/Die_Planchet_Abrasions.html
I do not accept that as a fact until you can prove mathematically that the striking pressure is lower simply because the collar is missing. Based on the images, it appears that the striking pressure is higher at the centers of the die and the loss of pressure becomes evident at the rims of the coins. That indicates that there is a pressure gradient across these off center struck error coins. Furthermore, posting a couple of error coins does not disprove that planchet irregularities are remnant at the high points of weakly struck coins across many series of US coins. The Jefferson Nickel is one series plagued by weak strikes. However, the planchet irregularities were such a problem that they even appeared on well struck Jefferson Nickels. Here are some examples: By all accounts, these three Jeffersons are well struck. Each coin has full steps and Monticello displays all doors and windows. The hair detail is strong on each coin yet we still see the quintessential surface roughness that plagued the jaw line of the Jefferson series. Now Doug, take a look at the last Jefferson, the 1944-P. There is a distraction of note on the collar of Jefferson's coat. It is small but sharp and well defined. Other than that lone mark, the only other relevant imperfections on the coin are the planchet flaws on the jaw. Compare the two! The planchet flaws are shallow an indistinct. Not to mention there are a multitude of them in one are of the coin, a coin that is otherwise nearly perfect. So how exactly does that happen. Here is your previous explanation. Well to use your words, I ain't buyin it. How many examples will you need to see of high grade Jeffersons with this phenomenon on the cheek before you realize that the only way those marks can appear is that they are remnants of the planchet surface. This same effect can be seen on just about every year of the Jefferson series at the exact same spot of the design with the the same general appearance. When you add it all up, planchet flaws is the only explanation that makes any sense.
Lehigh, there is another way to look at this. Your nickels are supposed to be well struck. Now compare the details of any one of your nickels to the weakly struck 1974 Doug posted in post #4 of this thread. That coin makes your coins look like mush. Even every window on his coin is full, sharp complete and deep. I am not sure I have seen a proof nickel that well struck.
OK, Doug. You don't believe me about the pressure, try this. Did you ever strap on a pair of ice skates a, step out on the ice and go gliding around on the ice? Well, guess what. You were not on very much ice, but mostly water. You see, your skates concentrate your weight to create enough pressure on the ice to cause it to melt. Now, that is one surface on top of another creating pressure. No 3 or 4 things to trap the ice and generate pressure as you say is required, but still the pressure causes the ice to melt. See http://www.helium.com/items/183484-the-science-behind-ice-skating. Here is a small quote from it;
To the contrary, I acknowldeged this point in post #42: The underlying point is this: A planchet isn't a perfect solid, its a malleable metal being struck by another harder metal (e.g. deformable body) so the formulas overestimate pressure. But not NEARLY enough to overcome the fact that the pressure increases linearly with the inverse of area. To use our example above, so maybe it's not 200psi, but rather 180 or 150 -- still more than 100psi! The point still stands. IMO.
OK, forget all the discussion.... LOOK AT THE COINS!!!!!!!!!!!! http://coins.ha.com/common/search_results.php?Ntt=off-center&Ntk=SI_Titles&N=51+790+231&Nty=1 You tell me if the off center strikes are stronger or not. It seems rather funny to me that we are even arguing this point....Mike
Someone with a microscope and a nice set of high grade jeffersons should take some 20x-100x photos of the cheek with planchet defects versus a contact mark. The difference will be obvious. Lehigh?
The rim of virtually all coins -- and certainly modern stackable ones -- gets beat up first. AND THAT IS KEY! You see a coin with perfect rims and some roughness that has that soft look in the "right" places, and you can virtually guarantee they are planchet marks. Looking at the coin under lights and magnification confirms it. Now you'll probably never believe me/us, and that's OK....Mike
I agree. Particularly this: "To differentiate between planchet abrasions and post-striking nicks, contact marks and mis-handling, examine the area closely to make certain there is still planchet luster (a whitish, frosty appearance) in the are of question. Also, zero in on some of the nicks, etc. (a 10X or 16X power loupe may be necessary) to see if they have the same color (luster), which would indicate they were there prior to striking, or if they are shiny, telling you that they were made by coming in contact with another coin (metal-against-metal). " Sound familiar?
We aren't arguing, but just discussing the relevance of off-center strikes to explain planchet marks during the striking process and post mint hits. Personally I think a little of both yours and dougs explaination fills the gap for me. I agree that usually you can tell the difference between a hit and a planchet mark. Now the question is how do they effect the grade? To me Pauls two pictures of nickels were a good example the first should grade higher than the second in my mind. Not that they could be the same technical grade - but to me the second with the hits would be 1 or 2 grades less than the first. Then you throw the tpg's into the mix and it makes it more complicated - at least to me. A fun discussion.
PS - it appears the more off-center the strike, then the better the possible strike. But they all have weak strikes away from the central design around the rims. Of course most are so far off center you only get a small piece of the central designs.
The flaws on Jefferson's jaw may not be planchet flaws. Could be caused by residue, moisture, dust and gas being pushed into the deepest recesses of the design by the pressure and metal flow during the strike.
OK, it seems the discussion here has run it's course, some very good points made but I was wondering about those on the fence regarding minute marks on the high points of the devices, that, is as to it's cause. Do you still feel is is some type of friction wear and then through handling, marks appear on the worn spot, or do you feel that these minute anomalies on the un-struck areas were left behind as part of the planchet making process?
To say or even think that planchet marks don't ever make it to a finished coin is foolish. But it is equally foolish to think that there are as many of these coins with planchet marks as the TPGs claim there are - as evidenced by their grading. n other words - it doesn't happen as often as they make out. And I believe that it is equally foolish to consider these coins worthy of the high grades assigned to them regardless of the cause of the marks. But that is an entirely different subject and discussion.
