ProfHaroldHill

5 hours ago, LINCOLNMAN said:

Another GIII. Evidently these were saved in quantity. 

Beautiful piece! Most of my favorite coins are the issues where so many nice examples remain, that it doesn't take a small fortune to obtain a really nice one. The great value still out there in high-end, non-US coinage drew me into the world coin arena, much like a kid walking past a candy shop who absolutely had to step inside.

An image is worth a thousand words.

On 9/30/2020 at 6:24 PM, physics-fan3.14 said:

Prof Hill: let me give you some feedback as an unwitting student in your class. 

I'll be honest: I find your obtuse and verbose prose irksome. 

I'd much rather you post a concise and collapsed summary than the dissertations you seem to prefer. 

You seem like the sort who loves the sound of their own voice. As a professor myself, I'm familiar with the type. I work with a few. They never cease to talk, and they rarely have anything to say. 

I hope this helps you in future interactions with people, here and elsewhere. 

And also - maybe, just maybe, some of us might know more about coins than you do. If you disagree, why the heck are you asking us a question in the first place? 

C'mon physics-fan, don't sugar-coat it. What do you *really* think?

Your 'druthers' are not my obligation to fulfill. I'm no professor, btw, I've but a high school diploma to my name. (Meredith Wilson?) Everything I ever learned, except the 'sex and drugs and rock and roll' parts, I learned on my own. (The CA public school system took care of the 'sex, drugs, etc', part.)

I'm normally a man of few words, actually. It was the warm affectionate attitude of the welcome wagon that set me to posting so much. I generally prefer to stay on topic, and not play soap opera games with one-trick ponies, but those beta type, 'bright-normals', like yourself, do fuss so at times.

'Cause you see professor, physics-fan... When I was a lad of but 14, at the request of a science teacher, a psychometrist came to my school one morning and tested me for placement in the 'gifted' program, which required an IQ of baseline genius, 135 on that 70's scale, or higher, for entry. I quickly rose to the top of that class too. They only assess to 165 for adolescents, and so essentially it means, '165 or higher'. But even at "just" 165, I've got a higher IQ than Albert Einstein and Stephen Hawking. (Published posthumous assessments.) That doesn't make me an astrophysicist, but it means that I can understand potentially anything humanity has to offer, if I desire to spend time at it.

You can wax poetic about knowing coins so well, but you don't seem to have the wherewithal to respond directly about this nickel. You posted more in your attempt at chastisement than in your prior posts, and you never once directly addressed the coin this thread you responded to is all about. A few others posted here they thought it was 'PMD', and they were polite and to the point. A couple made some good guesstimates at the reason for the coin's appearance.

It's easy for you to say 'nay', but if you can't or won't offer a better explanation than I have above, then you have no right to grandstand.

"I hope this helps you in future interactions with people, here and elsewhere."  No, you hoped only to somehow show yourself as superior, but you failed, big-time.

2 hours ago, Quintus Arrius said:

My dear Prof. HILL:

Some peoples' attention spans are short; they prefer eating to dining.

I for one am not about to expound upon the utility of the Socratic method, however known to you, and urge you to dissertate on coins, or any related topic you wish, at will.

I have found every matter you have presented to be interesting and the answers elicited to be of the utmost importance.

Sincerely,

Quintus Arrius

Postscript:  I was graduated early from both  high school and college when registrars reviewing my transcripts discovered I had more than enough credits to graduate. 

Thank you Quintas. That's much appreciated.

On 9/28/2020 at 7:03 PM, Conder101 said:

And they would send it to Fred.

Nickel had another coin stuck to it with something like say wax.  The other coin was offset and not directly covering the coin leaving a crescent exposed, but a little of the "wax"extended past the overlying coin along the left edge.  Then the coins were exposed to a corrosive environment.  This etched the exposed nickel down to a lower level and since the corrosive acted evenly the original details were retained.  The "wax" protected the rest of the surface frome the corrosive.  Then the coins were separated and the "wax" removed and the coin continued to circulate.

Thanks for your reply, Conder101.  Let me expand on my brief post earlier, reference 'Occam's razor'.

If we came upon a house with a broken window and a rock inside on the floor nearby, and we were offered the following two choices of explanation, which would we choose...? 

The first explanation being that someone threw a rock through the window and left after the window broke, the second explanation being that the window vibrated heavily as a truck drove by, (thus shattering the window,) and that the rock was there because a rock collector was sitting near the window earlier, then left the house, but forgot to take their rock with them.

Usually, the less cumbersome or complicated explanation is the accurate one. (Somebody chucked the rock and split!)

Someone would have to go to a lot of trouble to do all of what you described, to the coin, (for it to happen by chance, seems nearly impossible,) ...and that explanation/theory wouldn't account for the differences in rim height along the lower reverse, at any rate. So the idea of it being a result of chemical dissolution is problematic.  My postulation in the post up above is based on simple events that are known to occur fairly frequently in the manufacture of coins, with the mechanical assertions predicated on known, accepted, and scientifically verifiable principals, regarding the forces and the metals involved.

Look very carefully at LIBERTY before speculating. I'll get a different angle image later and add it.

16 hours ago, Conder101 said:

And they would send it to Fred.

Nickel had another coin stuck to it with something like say wax.  The other coin was offset and not directly covering the coin leaving a crescent exposed, but a little of the "wax"extended past the overlying coin along the left edge.  Then the coins were exposed to a corrosive environment.  This etched the exposed nickel down to a lower level and since the corrosive acted evenly the original details were retained.  The "wax" protected the rest of the surface frome the corrosive.  Then the coins were separated and the "wax" removed and the coin continued to circulate.

Google, "Occam's razor".

38 minutes ago, Moxie15 said:

Have you had a TPG look at this? 

I have no further thoughts on it. I gave what I thought and you have shown where I am missing the facts, that is cool I am used to being wrong. I would be interested in what another expert thinks as Fred W thought it was post mint damage and you think otherwise. 

You were certainly not the only one mistaken, here and elsewhere. You were though, the only one confident enough to offer a hypothesis thus far, here and at CU/PCGS. That was cool.

I should add that it's at least possible that the lamination detached while the coin was in some sort of coin-operated device of the kind you mentioned.

Wait til you see the obverse.  It's a tougher puzzle than the reverse, and raises the valid question, "Was it damage that broke the lamination free?"

(AND the question, "Did FW dismiss it, all the while knowing full well that the reverse was a planchet flaw?")

Stay tuned for the obv. I have to go move a few hundred pounds of winter squash before dark, (and cook dinner,) or I'd post it right now.

On 9/26/2020 at 4:42 PM, Moxie15 said:

I think this coin was caught or jammed into a machine such as a coin accepter/rejecter soon after it started circulation.  If the rejecter mechanism had a pushing finger with a face rounded to the same diameter and it pushed against this coin when it was jammed it may have caused this damage. I worked at a payphone company in the nineties and saw many mangled coins in payphones, I cannot say for sure this  was caused the damage but it could be possible. Especially as the left side as we view it looks to have been cut from the the bottom of the coin by a cutter moving upward towards the top of the coin causing the ragged appearance.

Thank you for this considered reply. Let me first say, that I began collecting coins in 1972 and by the late 70's I was beginning to buy and sell coins. After a brief hiatus for a pesky head injury, I resumed my dealings in the late 1980's right after NGC joined the scene, (I had and have no B&M shop, just worked as a 'Vest pocket' type.) I've seen countless coins, plenty of errors and far too many metal discs that once were coins, but now are just dinged-up or mangled relics of their former selves. So I have plenty of experience around coins.

But more than that, much more for purpose of this thread, ...there is, essentially, a small 'medieval forge and foundry' located less than 100 feet from where I write this.

My eldest son, when not leading a team of software engineers at some hifalutin' hi-tech firm down in Seattle, (or hand-making fine jewlery,) likes to cast precise copies of medieval daggers, as well as the handle pieces for the hand-forged steel long-sword blades we craft here. We have an antique forging 'anvil complex' from an old foundry that had to be brought in by truck. There are two crucible furnaces here, a small amateur type, and a large one suitable for single pours of large blades, et cetera. I have studied metallurgy and crystallography as it relates to metals, (all metals are crystals,) and I have examined many pours of molten metals, base and precious, and have seen first hand the results of improper heating, bad alloying, dross in the pour, and more. We haven't rolled out any ingots into coin strip, but I've examined many poured bars and studied the problem pours with loupe in-hand.

With that said, let me start by pointing out that your hypothesis doesn't account for the details visible on the coin in the area where the metal is missing. If something cuts or gouges the metal it will slice through the metal, it cannot possibly cut new digits into the metal left behind. But there they are, in relief to the 'new' surface, though fully beneath the plane of the coins original surface.

There is only one thing that can lead to features like the 'ghost image' of the Bison's leg, the 'ground' extending rim to rim even through the area missing metal, and those bold, in-relief digits with perfect little 'canyons' between them. (They're 3-dimensional, not flush with the surface. I hope they appear on your screen as they do on mine.)  It's not any form of mechanical damage that does that.

According to the Hall Petch relationship, the finer the grains of a metal, the more ductile and malleable is the metal. When we process metal for coins, we want it nicely 'workable' so the planchets easily reach the fluid state and fill out the recesses of the die completely. In a poor quality pour, the granules will be of mixed sizes, with many too large for good coinage use. This creates areas of potential faulting, and when the metal is rolled into a strip it can create table faults, just under the surface, or deep in the center. The near-surface table faults are what can break free and allow for a "lost lamination" flaw/error to occur.

If you google/bing/etc, "lamination error coins", Images, ...and look through the pics, you'll notice that a lot of them have 'ghost images' of the design details, visible even though the original surface is gone. (The lamination had to still be in place at the moment of striking, for the ghost images to exist of course.)

The 'images' are there because once the metal had filled the recesses in the die, the remaining energy from the strike (other than that lost to heat, or into the mass of the die base,) 'slams back' into the planchet to a good depth. This forces the molecules to begin aligning themselves in their crystalline configuration. Look at coal and diamonds. Both essentially pure carbon. To make a diamond, carbon is subjected to intense pressure/heat which places the molecules into a thermoplastic state, coaxing them into their most efficient formation, the crystal. A diamond.

Those crystalline columns down into the coin, are also exactly why "Nick-A-Date", date-restorer works on dateless Buffalo Nickels. It chemically etches away the surface, exposing the metal below, where the difference in reflectivity from varying levels of crystallization, allows us to make out the date on the dateless coin. (On some severe lost laminations, or 'delaminations', if you prefer, a 'pocket' forms, and you can see the rough outlines/details of the image struck into the other side of the coin.

The reverse side of this coin suffered a 'lost lamination' event. The missing metal may have fallen away just after striking, or it may have remained in place for a time, possibly even after entering circulation.

The question now apparent is, "Why did the metal break away in a crescent fashion?"

On 9/26/2020 at 4:49 PM, MarkFeld said:

Fred provides opinions on lots of coins and explanations for some of them. If he were to give an explanation for each one, it would take considerably more time.

And, though this is not directed at you, from what I’ve seen over a period of many years, in a large number of cases, it would be a waste of his time. Because the owners of the coins don’t usually want to hear informed opinions. Instead, they want to be told that they have something of value. You might be amazed at how many people argue with me when I tell them that their obviously abused coins aren’t one of a kind, valuable errors. I’m not talking about ones like yours, either - I can at least understand why you think yours is a legitimate error.

True. I've heard descriptions of a few of the 'parking lot finds' brought to him. One was directly from the slightly 'hurt' owner of the dinged-up cent. Mr W didn't mince words or go into a lengthy dissertation, if you get my drift.

I wasn't ruing his lack of participation, btw. Nor was I hoping to induce him into a 'busman's holiday', of sorts.  No, I actually only mentioned FW's one-word comment of 'disapproval' because Moxie15 had mentioned in another thread, (that doesn't contain mention or images of this coin,) that Mr W had condemned it at CU/PCGS some years ago. I added mention above in my OP because I didn't want Moxie15, or anyone, to think I would hide that.

When the market crashed in summer of '89 I had to start doing more than breaking slabs to make money with coins. Dealers were paying way below sheet, which was dropping weekly,) and byh the time I got my box of 20 'widgets' back, even if I'd gotten the upgrades I desired, I still often only 'broke even'. I started looking at everything in the shops I frequented, and wound up buying large bulk lots of low grade US coins that they'd normally ship off. The dreck that came in with the collections they bought, I "intercepted" by paying a 'penny' more per coin than the 'dump price'. A couple of the shops were seemingly skilled at missing some of the good stuff, (incl two low-end circ 14-D's and six 09-S, 4 22-D, LWC's, a G6 1913-S T2, an awesome 37-D 3-legged Buff that PCGS slabbed at EF40, as well as dozens of 'lesser' dates that I sold to 'Jake' or others via the US Mail.)  Between that and the occasional pick-off of a rare VAM, etc,  I managed to avoid having to go work at a "real job" in order to attain the needed funds for my kids and I. (Also assembled a 3# collection of tokens, most of which I can't find online, and a 1000+ pc collection of world coins that I kep out of the loop, when I began also buying their world coin bulk and selling it on at the same $5 per pound, sans my 'picks' of course.)

Even as the market returned, I was hooked on the little treasure hunts I got to have on a semi-regular basis, so I kept at it until about 10 years ago.

So I have looked at tens of thousands of coins, and I have seen seemingly countless damaged ones. Some gave pause for a moment, while most elicited only a grimace before I tossed each into my 'searched' bin. A select few though, I set aside. Most are common flaws in common configuration. A few are mint errors. A very tiny few, (count them on one hand,) are puzzling.

This 1937-P Buffalo is one of that elite. After my reply to Moxie15 next, I imagine some may begin to shift their opinions, certainly of me if not yet of the reverse of this coin. They might need to do a bit of googling first, to believe what they've read.

22 hours ago, Moxie15 said:

I think that much if not all of the visible damage in the picture is post mint damage. I am not sure of a minting process that would cause such damage. I think the coin has had at least two encounters. One could possibly have been before striking. You have the coin rotated 90% to the right, by the way. The damage near the top of the coin looks like it was done with a small cutting wheel or other abrasive surface. The damage along the rim that goes down toward the lower rim looks older, and of another cause. I very well could be wrong so I await a better theory.

Yes, the coin was rotated to get the best view of the anomaly, not provide a 'numismatic orientation', as you might say. Thank you for the detailed answer in reply. I'll return to this piece soon after I reply to your estimation above, regarding the reverse of the 1937 Buffalo.

5 hours ago, physics-fan3.14 said:

I find this to be a very good hypothesis. 

It would also explain why the metal appears "built up" around the curved edge, like the metal was pushed around. 

To the OP - show us a picture of the obverse as well. You are handicapping us by only showing one side. 

I'll post the obverse pics soon.

This ten cash from Hupeh Province... 

I'm curious about what you and @Moxie15 feel caused its odd appearance, PMD or flawed planchet, if you don't mind.

7 hours ago, Quintus Arrius said:

I can see history is repeating itself here.  One hapless soul who had the temerity to disregard super star Fred Weinberg's pronouncment -- the equivalent of a SO ORDERED as issued by a federal judge (which I take to mean is a major faux pas in polite society) was run out of town on a rail -- and I was excommunicated for simply insisting he should has his say however repetitious it had become. One enterprising lad went so far as to insist that I, whose lack of formal schooling could not be substantiated beyond the first grade, introduced malware that prevented numismatists, many notably prominent in their profession, from utilizing the scroll-on mechanism on their state of the art cyber-devices.

So, by all means, present your errors in your own likeable, inimitable style but beware too that at some point you will tread dangerously close to that hidden threshold of the Twilight Zone from which there is no return as an appeal mechanism has as yet to be devised permitting the disfellowshipped from rejoiningn their former congregations.

Wait! You can't be serious! Over a damaged coin?  Yes, sir. For nothing more than offering a seemingly plausible, alternative explanation for an explicable error.

Unless you can offer a cogent hypothesis on the piece, your sophistry will only be wasted here.

Start by explaining how you can remove metal from the lower reverse of this coin, without altering the underlying crystalline structure of the metal.

I look forward to hearing your thoughts on the topic.

8 hours ago, MarkFeld said:

While Fred isn’t correct 100% of the time, I don’t know of anyone else who’s more knowledgeable about errors. If his opinion isn’t good enough for you, who’s would be? Anyone who tells you what you want to hear?

This thread is for discussion of how the piece came to be as it is. I've owned it for over 20 years and never once thought it was worth large sums of money. It was years ago that Mr Weinberg offered his assessment, I didn't come running here after my ego was bruised, seeking validation or redemption, as some, if not yourself, seem to have surmised.

I will value the opinion of he or she who, with an elementary, but working understanding of metallurgical science, offers that opinion with an actual, descriptive explanation of what was involved in producing this anomaly.

Hero worship is for others. I made a modest but fair income for a quarter of a century, running circles around expert graders. 

Mr Weinberg is a good man, with a great sense of humor. He is unquestionably an accomplished professional in his field. He does not, however, spend time going into details about coins posted online that he deems damaged. If I could afford the luxury, I would send it to PCGS and request a detailed analysis. I can't.

So this thread exists in the stead of his further, detailed opinion, not to counter his initial opinion, except in a way that produces a better understanding, for myself and any who may be following along without posting.

Only the reverse at first, the obverse is also anomalous, but I wish to go one step at a time.  The coin, (images in a post at CU forums,) was declared simply as "PMD", by Fred Weinberg, without comment.

When looking at the coin, understand  that there is not simply a curved "cut" in this coin, going through FIVE CENTS, the coin is missing a significant amount of metal along the bottom of the reverse.  The surfaces of the lower parts of the letters of FIVE CENTS, are not the original surfaces. The entire crescent area, under magnification, shows marked haziness or roughness of appearance.

@Moxie15 I've decided to start a new thread for that nickel, I think it might be better than piggybacking this one. 

27 minutes ago, ProfHaroldHill said:

 

It's a 'rolled through' planchet flaw, I would now estimate. Occurring during the rolling/thinning of the strips in the planchet manufacturing process. Some foreign matter was on the surface as it was being drawn through the rollers, and its image was left behind. Perhaps a piece of wire. When the coin was struck, the 'image' was distorted by the dynamic forces of pressure. The 1 and ---script were mostly filled in, thanks to the channeling of metal flow along and through the recesses...

The reason I stayed away from the laminated planchet theory was, in part, due to the unusual nature of the depression, as you, (physics-fan,) note, and also due to the high quality of the coin. There are no streaks, no crystalline granular areas seen, and the bottom of the depression is bright and identical in color to the areas of least patination on the coin's surface.

It seems more a 'stretch' to have it fit the mold, so to speak, of a lamination flaw, than to conceptualize it as a flaw occurring during the blank production process.

On 9/24/2020 at 6:39 PM, physics-fan3.14 said:

Post mint damage wouldn't go "under" the devices as you show. A mark of that nature would affect the lettering as well. 

A lamination (or, delamination) is usually linear in pattern - it usually follows the rolled pattern of the strip before it was cut into planchets. This isn't necessarily always the case, but it is typical. Its unusual to see a lamination in the wavy pattern shown here. 

The problem with a strike-through is that it would also affect the devices. The pattern seems recessed into the coin, but a strike through would also affect the lettering (which appears crisp in your image). 

Thank you for your thought out reply. Glad we agree it's not PMD, and you're right about the strike through conflict. After another close examination, and essentially ruling out a strike through, it occurred to me that it may have happened when the strips were being rolled out before the blanks were punched. The tiny 'canal' ends right before the top of the rim, though the depth tapers away just before the edge.  There is that slight disruption of design at the 1 and where the canal "passes through" the -script. The edge is perfectly formed and smooth. It's actually reflective, this is a well struck tiny coin. 

It's a 'rolled through' planchet flaw, I would now estimate. Occurring during the rolling/thinning of the strips in the planchet manufacturing process. Some foreign matter was on the surface as it was being drawn through the rollers, and its image was left behind. Perhaps a piece of wire. When the coin was struck, the 'image' was distorted by the dynamic forces of pressure. The 1 and -script were mostly filled in, thanks to the channeling of metal flow along and through the recesses of the die.

I've accumulated a couple of dozen oddities over the 25 plus years that I've been working shops and shows. Some are obvious errors, but a few are essentially puzzles. None of them were purchased individually, nor was there any notice by the seller of their unusual nature, (except for a blank large cent planchet.) 

This is the first time I've had the opportunity to show and discuss them, other than a brief addition to someone else's thread over at the CU PCGS forum. 

Your input is appreciated.

7 minutes ago, physics-fan3.14 said:

Post mint damage wouldn't go "under" the devices as you show. A mark of that nature would affect the lettering as well. 

A lamination (or, delamination) is usually linear in pattern - it usually follows the rolled pattern of the strip before it was cut into planchets. This isn't necessarily always the case, but it is typical. Its unusual to see a lamination in the wavy pattern shown here. 

The problem with a strike-through is that it would also affect the devices. The pattern seems recessed into the coin, but a strike through would also affect the lettering (which appears crisp in your image). 

Where the anomaly goes through the -script and the 1 in the date, it caused a slight depression. The 1 dips slightly, as if sagging, where it intersects the anomaly. For some reason, the metal did not fill in the 1 completely, nor part of the -script and the design elements near the rim. 

OK. No way the anomaly here is from die chipping, but I couldn't have made up that spiffy title without a tad bit of 'literary license'. 

So... Strike-through, planchet flaw, or Post-Mint Damage? I say Strike-through. 

4 hours ago, Insider said:

I have not seen an encasement transfer design into the mid-parts of a coin.  It's interesting to speculate the cause.  It's just a damaged coin to me.   

Definitely damaged, but a good mystery to unravel in that the unraveling helps gain insight into the mechanics and the forces involved in coin, (exonumia, medal, etc) production. 

Though I did have to conclude that my original opinion was incorrect, the process involved in getting to that conclusion was educational and even a bit of fun. 

On 9/22/2020 at 2:50 PM, Moxie15 said:

I don't know if all what you say is true, @ProfHaroldHill, what I do know is that it looks similar to your buffalo nickel that Fred Weinberg called PMD  I have to give you point #2 as many, but not all coins claimed to be partial clips have cuts on both faces.

https://forums.collectors.com/discussion/860931/an-example-of-a-incomplete-clip-planchet-mint-error

I am surprised that they use two cutting surfaces as one sharp cutting surface often leaves a cleaner cut 

I'm actually going to post that nickel in this thread, but wanted to post these two first. 

I disagree, in part, with FW's assessment. The reverse is not PMD, in my opinion.

On 9/22/2020 at 12:55 PM, Insider said:

The dots made me consider an overstrike also.

I just learned that encased coins were/are made in a hammer and anvil type coinage-style press!  The blank aluminum holder, (in the shape of a circle, a horseshoe, kettle, 4-leaf clover, etc,) is fed into the press and a coin is placed in the hole in the blank. When the hammer die strikes, it stamps the advertising message into the aluminum and simultaneously forces the aluminum around the coin to seize the coin all the way around it's circumference. The hammer die has an empty recess to prevent contact with the coin as it strikes the aluminum holder. The only force that affects the coin is the compressive force as the aluminum clenches hold of it. The surfaces of the coin are never contacted by the hammer die.

Based on that, I'd wager that a coin, instead of being encased, got jammed in the hammer die and when it struck the next blank encased coin, the die drove the coin stuck to it down onto the other (this) coin as it stamped the aluminum holder with its message. It was wedged in the hammer die at a slight angle, so the imprint, (false die clash) only appears on the one side of the obverse. That area is also where the odd denticals and the dots appear.

The coins were almost in alignment when they were forced together, so the rim of the coin in the hammer die sliced into the rim area of this coin. (These were clean, BU coins at the time.) The denticals on the coin in the hammer die slammed into the denticles on this coin, and in that small area, the metal flowed in weird ways. It narrowed the denticles, by 'squeezing' some of the denticle metal back toward the center of the coin. (The dots may simply be a fluke of the metal flow as well.)

The reverse of the coin was protected the whole time because it was face down in the holder, held flush to the surface of the anvil dies base, with only its rims actually touching the metal.

On 9/22/2020 at 11:23 AM, Insider said:

HOWEVER, I've never seen denticals on an Indian head as show from 2 - 6.  They look like they have dots close to the edge above some of the teeth.

Those 'dots' have been a mystery to me from day one. At first I thought perhaps it was a coin struck on a foreign coin, the dots being 'residual' design elements of the 'original coin', (preserved due to the collar's seeming malfunction.)

The 'apparent clashing', (squeeze job,) and the denticle issue, may actually be from entirely separate events. I suppose I should count the 'denticles' and see if the numbers are correct for this issue. Maybe they are actual 'pre-denticles'.

8 hours ago, Moxie15 said:

I have two difficulties accepting your explanation of the curved line.

1. The curved line on the obverse follows a single arc until it hits the upturned rim then it changes direction into a different arc. If this occurred before the rim was upset the angle of the arc should not change but it would end into the upsetting.

2. There is a matching (or Nearly matching) arc on the reverse. Every punching tool that I have encountered has one cutting edge and one shear edge, not two cutting edges.  

Therefore I doubt that this was caused at the mint and would need further proof, or a further explanation of this.

Regarding Point #2, if you do an internet search you can find several examples of this error, and they have virtually identical incisions, obv and rev.

Re Point #1; The area where the L in Liberty should be, (where the 'line' ends,) is a valid point to bring up. It's an area that provides a 'pause factor', I do agree. Consider the following though: At the moment of striking, the metal is briefly altered from a solid state to a fluid state. The rim area is the highest point of the design on the Lincoln cent, (to protect the devices, etc, from wear, and to allow the coins to stack.) The metal filling the void that will be the rim, is subject to shifting forces due to the effect of the collar stopping the radial flow of the fluid metal and abruptly shifting its direction by 90 degrees.

There is significant missing detail there that does not appear to be from retained material, (grease, etc,) and it's in an area not subject to normal wear due to its proximity to the rim. My thoughts are that the deforming of the apparent 'line' occurred only at the surface, in the last nanoseconds prior to the metal's return to a solid state.

Leaving aside for a moment the above explanation, one has to ask how it would be possible to make such a cut into the surface, as seen above, without harming the rim in any way or distorting the design anywhere. I'm convinced this occurred before the striking, but I'm of course open to other theories/speculation.