Considering the large field of location for a mintmark in the Lincoln Cent Series. What is the probability of a mintmark being punched at the same location and in the same orientation on two different working dies in the same year? I am of the opinion that the probability of this occurrence is very slim (an aberration more or less) and that almost all varieties with few exceptions can be attributed just by determining the location and orientation of the mintmark in relation to all the other design devices of the coin.
Well, the answer lies within a question, actually. "With what precision?" Under typical conditions, say a 20X-30X microscope - I would say one in a thousand dies would receive a mintmark that was substantially close enough in position to a different die so as to make them impossible at this magnification to tell the difference between the two. Now that both would have the same spread as a repunched mintmark is a one in a million long shot...which is why mintmark position alone is not reliable unless far enough off to see under typical magnification. I know of a number of Lincoln cent repunched mintmarks that REQUIRE a 30X overlay to detect as being different from another, but I know of only one pair that is undetectable as being different dies at typical magnification even with an overlay. This pair of 1960D repunched mintmarks was only split with the keen eye and good detective work of John Bordner a number of years ago, and is currently listed as two different dies by many. The mintmark AND doubling are identical...the only thing that separates the two are die markers that happened in such a way as to prove that two different dies had to be used to create the coins. Unfortunately right now I do not remember the die numbers for this rare occurrence. A simple example of a doubled die that remarkably resembles another, thus die scratches and gouges have to be used to detect them as different would be 1972P-1DO-003 and 1972P-1DO-008. The spread of doubling on these two dies is so similar, they are virtually identical even under magnification. Again, the only thing that definitely separates these two dies are markers that could not have all occurred on the same die.
Scientifically I would half way agree but, Scientifically I would tend to agree but, "that specific location" is not Nearly as easily detectable as other die markers or the D/D itself. Yes the field is large and many, many dies are made several thousand in recent times but as often as they are re-punched, they also got it pretty darn close. Remembering the mint is a factory that produces it's machined parts as good as it can, or in this case could. Many technicians got pretty good at it - as anyone would if they did it thousands of times. I have not been to the die shop as Margolis and others have but have the books and I've tried to imagine how it would be to do this operation - remembering the die is a negative (encuse) image. Also keeping in mind that it may take several blows from the punch to fully seat the "D" or "S". Lets not forget the finished working die while a negative design is also slightly conical so the punch (as I understand it) would need to be slightly "rocked" into the die - not an easy task but it's not heart surgery either mint workers should have been able to perform this task pretty darn good especially with experience. There is only 2 things that can explain all the RPM's that we have, especially in the early sixties is, 1. they did not make it a priority, or 2. they had many differnt people doing the job, ( I guess that could qualify as the same answer if you get my meaning). After many discussion's with Bordner, Potter, Crawford, and others is - If they got it working well into the late 1970's and 1980's they should have had at least the knowledge back in the sixties and before to do the same thing. I would not want to have to attribute by location of mint-mark alone within the field, for me, that just would not give enough data to do the job right but in theory I think what you are saying is true. To do so as you suggest you would have to have some kind of template that would sit stationary with like 30x and study each coins mintmark location - thank goodness we have easier ways to do it. Sorry I got a little long winded,
Taking this one step further Think of a working die as a finger Think of each coin struck by that working die as a fingerprint I am suggesting it’s possible to attribute all Lincoln Cent mint marked working dies used in 1989 and prior (not only varieties) with just a few exceptions by obtaining the following information 1. The Date 2. The Mintmark ("D" or "S") 3. The Mintmark's location in relation to all other design devices on the coin 4. The Mintmark orientation (whether punched – clockwise, counter-clockwise, etc.)
Interesting concept. I think there are a few factors to consider. 1. If 2 different die mintmarks did overlap with precision beyond detection, how would you know? Since study is done after the fact, even other diagnostics like scratches, polishing marks, chips, etc. could be considered different die stages rather than different dies. 2. The dieworker had experience and practice, and probably struck 99% of the marks with correct orientation and within a very small area of deviation in the designated area, so the % that would be indistinguishable should not be estimated from the total area available for a "normal" mintmark. 3. Die deterioration tends to distort the mintmark through die use, and would make determinations difficult. Also wear on a coin tends to increase the width of the mark due to the sides not being true vertical ( except for some proof coins maybe). On the other side, it hasn't been too long that good digital cameras and photo programs that can measure distances in pixels (or what ever) have become readily available to allow someone to undertake such a study. Such a study of 1960D cents would probably fill a book.:thumb: Jim
Justafarmer - Add to your list the 'plumb' of the mintmark punch to the die. Not only do many mintmarks sit slightly rotated CW or CCW, but they can also sit slightly tilted top heavy, bottom heavy, or to either side. Then you would have a #5 to look for. With precise laser imagery and a lot of programming, this would definitely be possible. Likely not worth the time and expense, but possible nonetheless. Desertgem - Your first point is a bit confusing to me. If we are talking about mintmark positioning on two different dies being too close to one another in position to detect them as different dies, we then go to the markers. of course every different stage of every different die would have to be plugged into this system, but it is actually rather easy to take two different coins from two seemingly identical dies and point out that they could not have been struck by the same die with markers. Just because one marker doesn't match another, we don't just call it a different stage. Markers tell a story of a die's life. If chapter 4 on one coin is a completely different story than chapter 3 on a different coin, they are different books...simple as that. On your second point...yes a die worker can punch mintmarks pretty close in-line with one another...but not nearly close enough that precise laser readers couldn't see the difference. VERY unlikely. And even if it was undetectable, any scratch, gouge, crack, or other marker the laser sees would tell for sure which die is which. On your third point...you're right. That's why every different stage and die state of every die would have to be a part of this system before it could work. The machine would also have to be able to detect wear and account for the wear when working through detecting to which die the coin belongs.
I guess my thought was if the 2 dies ( lets use A & B to distinguish) had identical mint marks locations, and "A" developed a die break immediately in use, from rim to lincoln's head. When the collector started looking at coins from these 2 dies, it would appear that it was just one die and it developed a die break in a later stage...rather than almost all of die "A" coins had it, and none of die "B" coins had it. If there were no other markers, and I have noticed that sometimes occurs in the diagnostic books, the idea of a die break coming in a late stage would be accepted. I do realize that most often there are more than 1 marker. ... Or maybe it just isn't a good idea of me posting on CT during breaks from the tax preparations JIm
Actually there is ALWAYS something you can use to identify a coin to a die. It's just a matter of how closely you look and how well you can pay attention to detail. Some fleck mark or some tiny gouge will be on one coin with the crack on the other coin - if you're really watching you'll notice they are from two different dies. It's not hard, really.
There seems to be a somewhat general agreement here. Is this unique to the Lincoln Cent? Do any other coins, by nature of their design, make the probability of a mintmark being punched at the same location and in the same orientation on two different working dies in the same year unlikely. Choose a coin and give an explanation - why or why not. I’ll start the exercise. Jefferson Nickel – (NOT a good candidate for mintmark deviation). The target field for the mintmark is narrow and the devices of Monticello (the steps and east edge) provide a good sight line for the punch. Exception being war time nickels when mintmarks were punched above Monticello. Kennedy Half – 1965 and after (GOOD candidate) – has a large target field and the bust is angular at the mintmark location making it difficult to be consistent with the punch.
Since the process was the same from denomination to denomination, there's no doubt the conversation would be the same as well. I see no difference at all in any of the above conversation if Lincoln cent were replaced by any other denomination.
