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Alloy Errors Intrinsic Metallic Inclusions

Part V: Planchet Errors:

Alloy Errors:

Intrinsic metallic inclusions

Definition: An intrinsic metallic inclusion includes all situations in which metal of a non-standard composition somehow resists melting or otherwise manages to maintain its integrity within the molten alloy.

This 1948 cent displays a large strip of light gray metal running across the obverse face. Close inspection reveals that the metal inclusion is an intrinsic part of the coin metal strip, present from the very beginning. It probably represents a globule of unmixed zinc or tin.

This is another intrinsic metallic inclusion that was found on the reverse of this 1944-P Lincoln cent.

Images are courtesy of Heritage Auctions.

MD-6

Retained cud diagnostics sometimes leave room for

doubt

By Mike Diamond – Special to Coin World | Jan. 10, 2011 9:00 a.m.Article first published in 2011-01-24, Expert Advice section of Coin World

Close-up image depicts the obverse face of a 2010 Millard Fillmore dollar with a retained cud at 7:00.

Mike Diamond

Dies are subject to brittle fracture, and this occasionally leads to a piece of a die face breaking off. The general term for such errors is “die break.”

The corner of the die (where die face meets die neck) is particularly vulnerable to breakage. A die break that carries off the rim gutter and at least a little bit of the adjacent field is called a “cud.” Coin metal flows into the resulting void, leaving a lump on the coin’s surface that is also called a cud.

Occasionally, a loose fragment that breaks off the corner of a die does not fall away but is instead held in place. It is then termed a “retained cud.” In the case of the anvil die, the die fragment is held in place by the collar. In the case of the hammer die, the die fragment is held in place by the bolts or clamp that secures the die shaft. Retained cuds of the hammer die are quite rare.

Despite the frequency with which retained cuds occur, misidentification is frequent both in and out of “slabs” (grading service capsules).

In order to diagnose a retained cud, there must be clear evidence of movement. The two key diagnostics to look for are vertical displacement and horizontal offset.

Vertical displacement is more commonly encountered. A retained die fragment will usually sink below the level of the intact portion of the die face. This leaves a “step” on the surface of the coin at the site of the break. The portion of the coin struck by the retained die fragment is consequently elevated above the rest of the coin.

The illustrated 2010 Millard Fillmore dollar shows a retained cud in which the letters e tru (of we trust) sit on a low plateau. Vertical displacement is evident all around the break. It is one of two examples struck by the same broken die sent to me by Fred Weinberg. Remarkably, each example also lacks an edge inscription — a completely unrelated error since the edge device is applied after the coin is struck.

More severe vertical displacement is seen on a retained cud that bisects the obverse face of a 2001-P Roosevelt dime illustrated here. The left side of the break also shows the second diagnostic — horizontal offset. Contiguous portions of the design are out of register with each other, documenting sliding movement on the part of the loose die fragment.

The reverse face of a 1985 Lincoln cent shows a large cud in the southeast quadrant and an arcing, rim-to-rim die crack in the northwest quadrant. Also called a “pre-cud” die crack, it shows neither vertical displacement nor horizontal offset. It simply shows lateral spread. The tenuously connected portion of the die splayed outward, producing a wide crack into which coin metal flowed. This left a jagged raised line on the coin. When the crack is even wider, it is designated an asymmetrical split die.

Arcing rim-to-rim die cracks and asymmetrical split dies are often mistaken for retained cuds.

When horizontal offset or vertical displacement is present and involves the entire margin of the break, the long-standing assumption has been that the die fragment was fully detached. But this conclusion may not always be correct, especially when the signs of movement are modest. Die steel is subject to bending, compression and distortion. This can produce some degree of vertical displacement or horizontal offset even when the die is still in one piece.

Vertical displacement within an intact die can be seen on the illustrated 2007-P Roosevelt dime. It shows a long, curved bilevel die crack on the face struck by the obverse (anvil) die. A later die stage has the same crack connecting with the rim at 6:30 to form what we would ordinarily diagnose as a retained cud. But is it really?

At least seven 2007-P Roosevelt dimes with presumed retained cuds of the obverse (anvil) die are known. Are all of them fully detached? I have my doubts.

Since we can’t directly observe the condition of the die that strikes any coin with a presumed retained cud, we must admit to an element of uncertainty in all but the most severe cases.

Coin World’s Collectors’ Clearinghouse department does not accept coins or other items for examination without prior permission from News Editor William T. Gibbs. Materials sent to Clearinghouse without prior permission will be returned unexamined. Please address all Clearinghouse inquiries to cweditor@coinworld.com or to (800) 673-8311, Ext. 172.

http://www.coinworld.com/articles/retained-cud-diagnostics-sometimes-leave-room/

MD-1

Rolling fold is a distinctive form of planchet burr

By Mike Diamond – Special
to Coin World |
Jan. 17, 2011 9:00 a.m.

Article
first published in 2011-01-31, Expert Advice section of Coin World

Reverse face of a 1972-D Jefferson
5-cent coin has a rolling fold upon which the letters e plu were struck.

Images by Heritage Auctions.com

The blanking operation involves a long strip of coin metal passing beneath a battery of blanking dies (punches) and above a perforated base plate. Each blanking die forces a disc of metal through the hole underneath.

In order for a coin blank to be punched out cleanly, the blanking die and the hole in perforated base plate must have smooth, sharp edges. If the edge of either element gets dull or chipped, this could prevent a blank from detaching from the coin metal strip. At the very least, it can leave an irregularity — a burr — poking up from the newly punched blank. That burr will then be folded over during the upsetting operation and, ultimately, struck into the coin. At this point the error is known as a “rolling fold.” Identified, described and named in the 1990s by error researcher Arnold Margolis, rolling folds are distinct from other types of burrs that affect blanks and planchets.

As seen in the illustrated 1972-D Jefferson 5-cent coin, a rolling fold is a
low, broad, symmetrical tongue of metal that intrudes a short distance into the field. Few are larger than this one.

Some rolling folds are too small to even reach the field and are thus restricted to the design rim. As is true of any struck-in piece of metal, this rolling fold is flush with the field and surrounded by a fissure.

No disturbance is ever seen on the portion of the edge adjacent to a rolling fold. This is in marked contrast to burrs that form later in the minting process. Called “rim burrs,” these can theoretically be generated by the upsetting mill, the feeder finger, or any other moving part encountered prior to striking. Judging from groups of coins I’ve examined with identical-looking rim burrs in identical locations on the face struck by the hammer die, a significant percentage of such errors must be generated by the feeder finger immediately before the strike.

The illustrated 1972 Kennedy half dollar shows a classic rim burr invading the last two digits of the date. It takes the form of a long, narrow spur with a sharp tip. The edge of the coin is gouged and the design rim is damaged, exposing the copper core.

A second rolling fold is seen on the obverse face of a 1967 Washington quarter dollar. The copper-nickel clad composition of this coin provides additional diagnostics. The reeding is intact and the edge undisturbed. The copper core does not extend onto the rolling fold, a characteristic common to all clad coins with rolling folds. In contrast, rim burrs often carry along a significant amount of copper core material.

The rolling fold in this example lies on the face derived from the original upper face of the coin metal strip. We can tell this is the case because the reverse clad layer has been dragged onto the edge a little bit, obscuring some of the copper core. This effect occurs on all clad coins and occurs when the blank is forced through the hole in the perforated base plate.

The presence of the rolling fold on the upper face is consistent with a blanking die that was dull or that had a small chip on its edge. Theoretically, rolling folds should be largely or exclusively restricted to the face originally impacted by the blanking die, since it is only here that a vertically oriented burr can form.

Rolling folds are quite rare, but you wouldn’t know it judging from eBay listings. Many errors on that auction site are identified as rolling folds but are something else entirely. Some are rim burrs. Some represent other forms of pre-strike damage, as seen on this 1966 Washington quarter dollar. On this example a wide flap was torn up and folded over, but it occurred after blanking. Some purported rolling folds are lamination errors while others are retained cuds. And some represent post-strike damage.

Collectors in search of a bonafide rolling fold must carry in their heads the handful of critical diagnostics described here.

http://www.coinworld.com/articles/rolling-fold-is-a-distinctive-form-of-planche/

MD-7

Crescentic plateau emerges from Proof polishing

mishap

By Mike Diamond | Jan. 31, 2011 9:00 a.m.

Article first published in 2011-02-14, Expert Advice section of Coin World

Obverse face of a 2009-S Northern Mariana Islands quarter dollar exhibits a raised crescent at its northern pole. It appears to represent a mishap during polishing of the field after the frosted texture was applied to the design.

When Clair Alan Hardesty received his 2009-S Proof set, he immediately saw that something was wrong with his Northern Mariana Islands quarter dollar. A thin, bright line could be seen arcing across the obverse face, cutting through the legend united states of america. The end-points of the line coincided with the inner margin of the design rim and extended from a point above the t of united to the e of america.

Recognizing it as a probable die error, Hardesty sent the coin to PCGS under their Mint error service. The response was disappointing and confusing. A customer service representative informed Hardesty that the grader had determined that “this is not an error coin. They are as struck.” Hardesty insisted that they look again, and the second response was similar, “The coin was re-evaluated for the error a second time. The information you provided was taken into account. Unfortunately the graders did not feel it was an error.”

Undeterred by the failure of PCGS to recognize a grossly obvious flaw, Hardesty sent the coin tome for analysis. Upon receiving the coin I immediately agreed that this is a significant die error. We next had to determine what kind of die error we were dealing with.

The bright arc is actually a sharply defined step. The crescentic area demarcated by the step is raised above the rest of the field. This indicates that the corresponding field portion of the die was recessed. The field has a mirror-like Proof finish above and below the step. However, faint radial ripples distort the surface of the abnormally polished crescent.

How was recess formed?

The question now turned to how this recess formed. A die dent seemed unlikely as this would have probably dulled the finish. A major clue as to what transpired can be found in the letters that cross the step. Above the step the letters are narrowed or constricted. This is most evident in the letters sta of states and the word of. Thinning of design elements is caused by only one thing — mechanical removal of the field surrounding each design element. As the field is lowered on the die face, the letters get narrower. This is because the sides of each letter converge as you go deeper into the die face.

The available evidence indicates that the step and recessed crescent were caused by a mishap in polishing the die face to a mirror-like finish. Die polishing is the exclusive province of Proof dies and dies that strike collector issues, like the coins in the Special Mint sets issued from 1965 to 1967. The intent is to create a highly reflective surface on the die and on the coins it strikes. If taken too far, this process can cause thinning of design elements and loss of details in the lowest parts of the design.

Die polishing of this sort should not be confused with intentional die abrasion designed to remove clash marks and other forms of die damage. Primarily applied to circulation-strike dies, such salvage attempts typically leave lots of die scratches and certainly don’t produce a mirror-like finish. The term “die polishing” is still sometimes used to refer to such salvage efforts, causing interminable confusion among collectors.

Alternative scenario unlikely

Hardesty proposed a slightly more complex scenario to explain this unusual error. He suggests that a strongly misaligned obverse (hammer) die collided with the top of the collar and that this collision left the step and the recess. He then suggests that Mint workers tried to salvage the die by polishing the damaged area.

A scenario involving collar clash and a subsequent repair job seems unlikely to me. It makes no sense to a repair such a heavily damaged die. There are no recorded cases of collar clash this offset and this severe among circulation strikes. A die dent generated by such a collar clash is unlikely to produce such a sharp step. Finally, the outer margin of the obverse die face retained its convexity (leaving a bowl-shaped perimeter on the coin). A collision as severe as Hardesty proposes should have flattened out that convexity.

Since die errors are repetitive, it is possible that more of these 2009-S Northern Mariana Islands quarter dollars remain to be found.

Coin World’s Collectors’ Clearinghouse department does not accept coins or other items for examination without prior permission from News Editor William T. Gibbs. Materials sent to Clearinghouse without prior permission will be returned unexamined. Please address all Clearinghouse inquiries to cweditor@coinworld.com or to (800) 673-8311, Ext. 172.

http://www.coinworld.com/articles/crescentic-plateau-emerges-from-proof-polishi/

MD-8

Lump on Jefferson’s head signifies a collapsing die face

By Mike Diamond | March 26, 2011
10:00 a.m.Article
first published in 2011-04-11, Expert Advice section of Coin World

This 1988-P Jefferson 5-cent coin shows a sizable lump at the top of Jefferson’s head that represents a die subsidence error.

Image courtesy of Mike Diamond.

Collectors of minting errors and die varieties frequently encounter coins with one or more featureless lumps in the field or on the design. Determining the nature and origin of such lumps isn’t always easy.

The two 1988-P Jefferson 5-cent coins selected for this week’s column present such a diagnostic challenge. Each shows a large swelling with a smooth surface at the top of Jefferson’s head. The border of each swelling is fairly well-defined. The outlines of the two elevations are similar, but not identical.

I initially thought that the two lumps represented two stages in the growth of the same defect on the same die. One example shows modest development of die flow lines consistent with a middle-to-late die state. The second example has heavy radial flow lines consistent with a very late die state.

However, a close comparison of the outlines of the two lumps revealed differences that could not be reconciled with progressive growth. Some fingers that extend out from the main body of the lump grow smaller from the earlier to the later die state. The border is also less clear in the later die state example. There are no common die markers; instead distinctive die markers on each example show that they were struck by
different dies.

The lumps certainly weren’t interior die breaks. Although the border of each elevation was fairly well-marked, they didn’t show the clean, jagged lines of a die break.

They clearly weren’t die dents. It’s virtually unheard of for two near-identical die dents to form on two different dies (the “extra leaf” 2004-D Wisconsin quarter dollars are a notable exception). Die dents this large are exceptionally rare, and finding two of this size is highly improbable. Finally, we find emerging from each lump several narrow fingers that merge with the waves of Jefferson’s wig. A die dent would not coincide with or merge with the hair pattern.

The lumps are too large, too tall and the surfaces too smooth to represent die erosion pits. The latter sometimes form in late die states, leaving small “patches” or “blebs” on the coin’s surface. Die erosion pits are very flat, with a rough surface and highly irregular boundaries. They usually form in the field. They may be related to loss of carbon (“decarbonization”) from the surface of the die face.

These lumps clearly do not represent trapped gas bubbles (“occluded gas bubbles”). Such planchet defects tend to be quite small and the distribution pattern will be different on every coin.

The one remaining possibility was a “die subsidence” or “sunken die” error. Here portions of the die face deform and sink in as the result of defective die steel or faulty die preparation. Sometimes the design fades out or disappears completely in the affected area, an effect readily apparent on our two 5-cent coins.

Perhaps the wrong type of steel was accidentally selected and extruded into a rod from which the working dies were cut. Perhaps the steel wasn’t forged properly, producing abnormal levels of carbon in the alloy.

If the steel was of the proper type and was properly forged, then a flaw could have arisen during any number of steps in die preparation. Improper annealing, tempering and quenching can alter the crystalline structure of the steel so that localized soft spots are left just beneath the surface. These only become apparent after the die has been placed into service.

Since two different dies from the same Mint and the same year developed two nearly identical zones of collapse in the same area, this would point to a problem more widespread than a single working die. Perhaps the dies were cut from the same defective rod of die steel, or were prepared by the same technician under the same faulty conditions. Since the lump is well-developed in a die that doesn’t show particularly heavy wear, it’s
clear that this abnormality represents something other than normal die
deterioration.

Sunken die errors are highly variable in shape, size, relief and location. While usually localized, the problem can affect the entire die face. In many cases the margin of the sunken area develops cracks, and some of the best examples straddle split dies.

Coin World’s Collectors’ Clearinghouse department does not accept coins or other items for examination without prior permission from News Editor William T. Gibbs. Materials sent to Clearinghouse without prior permission will be returned unexamined. Please address all Clearinghouse inquiries tocweditor@coinworld.com or
to (800) 673-8311, Ext. 172.

http://www.coinworld.com/articles/lump-on-jeffersons-head-signifies-a-collapsin/

MD-2

Centralized, bifacial design weakness can have many causes

By Mike Diamond | April 02, 2011 10:00 a.m.

Article first published in 2011-04-11, Expert Advice section of Coin World

A weakly-struck 1961-D Lincoln cent displays a smooth bust of Lincoln on the obverse and an incuse ghost of Lincoln on the reverse. Its weight is normal.

Images courtesy of Mike Diamond.

Some months back (Dec. 20 issue), I devoted a Collectors’ Clearinghouse column to an assortment of errors that share the same end result — weakness and loss of design elements at one pole and on both faces. This week’s column focuses on a somewhat different assortment of errors that produce weakness and loss of centrally located design elements on both faces.

For a planchet of normal size, weight, thickness and density, the most common cause of centralized weakness is a weak (low-pressure) strike. The illustrated 1961-D Lincoln cent is a typical example.

Lincoln’s bust is devoid of details. On the opposite face, a vague, incuse ghost of Lincoln was formed when coin metal bulged upward toward the recess in the obverse die and away from the reverse die. There simply wasn’t sufficient tonnage applied to the planchet to redistribute the amount of metal necessary to fill all the recesses of both dies. Persistence of the original proto-rim of the unstruck planchet provides additional evidence of abnormally low striking pressure.

A planchet punched out of rolled-thin stock will often end up looking like this 1961-D Lincoln cent. Overall effective striking pressure is reduced because the planchet is closer to the minimum die clearance and because the force delivered by the press “knuckle joint” tails off as the latter approaches maximum extension. Of course, any coins struck on thin planchets will be underweight.

Centralized weakness in conjunction with a well-formed design rim points to an entirely different scenario. This combination of features is seen in a 1983-P Jefferson 5-cent coin found by 15-year-old Alex Ness while roll-searching. The side of Jefferson’s face looks scooped-out and lacks all detail. On the reverse, the portico of Monticello is nearly smooth.

In this case, I suspect striking pressure was normal but that the planchet was too hard.

If a planchet is not sufficiently annealed prior to the strike, it resists plastic deformation.

I have seen photos of one other 1983-P Jefferson 5-cent coin with well-formed design rims and with the centralized weakness even more exaggerated. It was evidently struck by a different die pair since the Mint mark is slightly tilted. Finding two examples with the same peculiar appearance and carrying the same date and Mint mark suggests that a load of abnormally hard planchets was delivered to several presses.

A weak strike that leaves the center of the design so poorly defined will also generally show weakness in many other areas, including the design rim and adjacent design. Also, weak strikes are quite variable with respect to how much detail is present.

Since coins struck through compacted die fill (“grease”) on both faces are rather common, one might assume that this could be a frequent cause of centralized, bifacial design absence. That assumption would be incorrect. Grease accumulations strictly confined to the center of both faces are actually quite rare. When grease is the culprit, it generally finds its way to other areas of the die face. Grease also tends to be asymmetrically distributed.

On rare occasions, centralized design loss is caused by a collapsing die. While a “die subsidence” or “sunken die” error can occur anywhere (April 4 issue), it frequently develops in the center. The center of the die is the last area to heat up during annealing and tempering, and the last area to cool during quenching. Uneven heat treatment can leave an area of abnormally soft metal in, the center of the die neck, and the die face can collapse into it during a press run.

The illustrated 1974-D Roosevelt dime shows a split die that bisects a smooth bulge on the side of Roosevelt’s face. This part of the die face sank in while simultaneously losing fine details. During the strike, as coin metal rose to fill the abnormal recess in the obverse die, it simultaneously withdrew from the reverse die, leaving a smooth hollow in the middle of the torch.

Split dies often straddle die subsidence errors. It is not known if the collapse of the die face precedes, follows or occurs simultaneously with the splitting of the die neck/shank.

Coin World’s Collectors’ Clearinghouse department does not accept coins or other items for examination without prior permission from News Editor William T. Gibbs. Materials sent to Clearinghouse without prior permission will be returned unexamined. Please address all Clearinghouse inquiries tocweditor@coinworld.com or to (800)
673-8311, Ext. 172.

http://www.coinworld.com/articles/centralized-bifacial-design-weakness-can-have/

2011 04 18

Dimpled Andrew Johnson Presidential dollars defy diagnosis

By Mike Diamond | April 09, 2011,10:00 a.m.

Article first published in 2011-04-18, Expert Advice section of Coin World

Dimples extend inward from all the peripheral letters and numbers on the obverse face of this 2011-D Andrew Johnson Presidential dollars. The dimples were apparently produced by corresponding elevations on the field portion of the die. The origin of these elevations is unclear.

Images courtesy of Mike Diamond

In my capacity as an error researcher I am frequently confronted with unfamiliar and, at times, inexplicable errors. It is an experience that most longtime collectors and researchers find familiar.

My colleague Robert “BJ” Neff was recently handed a doozy of a mystery by error dealer Fred Weinberg. He sent Neff three 2011-D Andrew Johnson Presidential dollars that show a peculiar effect on the obverse face. All of the peripheral design
elements display a shallow dimpled field along their inner side. In other words, the dimples form a centrally directed, converging radial pattern. The effect is easily seen in the accompanying photos, all of which were taken by Neff.

The first problem to address was whether these dimples represented a die error, a planchet error or a striking error. It was immediately apparent that the anomaly was present on the die face. The dimples are identical on all three dollars, and a careful study of die markers undertaken by Neff showed that they were all struck by the same die pair. The presence of dimples on the coin means that the field portion of the die face must have been elevated right next to each peripheral design
element.

But what could produce such elevations? My thoughts initially gravitated toward some form of die deterioration doubling. Incuse forms of die deterioration doubling are known among copper-plated zinc cents and on some state quarters. But I’ve never seen a case in which the incuse doubling is located along the inner margin of the normal, raised design elements. Most of the time the doubling extends from the lateral margin of the affected design elements.

Finally, incuse die deterioration doubling is associated with other signs of die deterioration, such as a swollen field or concentric ripples in the field. None of the Andrew Johnson dollars show signs of die deterioration; they seem to conform to an early die state. Still, I can’t entirely dismiss a novel form of premature,
incuse die deterioration doubling.

Could the defects have been present on master die or a working hub? Probably not, since we’d then expect the dimples to be more widespread among Andrew Johnson dollars. Right now it looks like the dimples are restricted to a single working die.

I had to abandon the idea that the dimples were caused by an abnormally soft working hub or an abnormally hard working die. Either could result in slight compression of raised elements on the face of the working hub and possibly displace enough metal alongside each element to a form pressure ridge. However, were that pressure ridge to be driven into the face of the working die, it would leave a recess. And that, in turn, would leave a bump instead of a dimple on the coin.

Neff has speculated that the dimples arose during the final phases of hubbing as a result of uneven cooling and contraction of the working die face. He correctly notes that the working die heats up during hubbing as the harder working hub forces its way down through the cone-shaped face of the unfinished working die.

After the “squeeze” is completed, the working die begins to cool and, according to Neff, contracts ever so slightly. If the cooling and contraction is uneven and particularly severe, one side of each peripheral recess on the working die face might find its way blocked by the corresponding raised element on the face of the working hub. This could cause a slight pressure ridge to form before the hub is lifted off the die face. The pressure ridge would be responsible for the dimple on the coin’s surface.

While this scenario is possible, I would have expected the phenomenon to have appeared before now and to be much more common.

Until we have a better understanding of the nature and origin of these dimples, it’s best to assign them a nonspecific designation. I would suggest something along the lines of “dimpled design extensions” or “design extension dimples.” While I’m not a great fan of placeholder terms, it’s the best we can do. We certainly wouldn’t be alone in this. After all, astrophysicists have applied the terms “dark matter” and “dark energy” to phenomena that they don’t understand.

I invite the readers of this column to submit other examples of dimples. Perhaps other dies will show the effect. A larger, more diverse sample might illuminate the situation.

Coin World’s Collectors’ Clearinghouse department does not accept coins or other items for examination without prior permission from News Editor William T. Gibbs. Materials sent to Clearinghouse without prior permission will be returned unexamined. Please address all Clearinghouse inquiries to: cweditor@coinworld.com or to (800) 673-8311, Ext. 172.

http://www.coinworld.com/articles/dimpled-andrew-johnson-presidential-dollars-d/

2011 04 25

Two-headed, two-tailed ‘pseudo-mules’ delight and

deceive

By Mike Diamond–Special to Coin World | April 16, 2011 10:00 a.m.

Article first published in 2011-04-25, Expert Advice section of Coin World

This triple-struck undated Jefferson 5-cent coin received two successive and fully overlapping off-center uniface strikes. The coin flipped over between the second and third strike.

Among the rarest of all errors are two-headed and two-tailed mules (mules are coins struck by mismatched dies).

Only one double-obverse (“two-headed”) mule is known among U.S. coins — an 1859 Indian cent. Only three known double reverse (“two-tailed”) mules are known — two copper-nickel clad quarter dollars and one copper-nickel clad dime.

These mules owe their existence to the accidental or intentional installation of two hammer or two anvil dies. But at least three other pathways can lead to a two-headed or two-tailed coin, and none require mismatched dies. One pathway is illustrated by an undated Jefferson 5-cent coin provided by Scott Taylor.

The first strike was normal. What initially looks like a second strike is 90 percent off-center and carries raised, normally oriented obverse design elements on each face. The two designs are almost perfectly aligned in vertical space.

Numerous clues demonstrate that the off-center designs were not generated by a muled pair of obverse dies. Next to the centered obverse face, the off-center strike is strongly convex and shows a matte texture. Design elements on this face are slightly expanded and flattened. All these clues indicate that this area was struck against another planchet. Finally, die markers are identical on the centered obverse face and the crisper of the two off-center obverse designs.

This 5-cent coin exhibits an off-center pseudo-mule (false mule) struck in a press with a normal die set-up. It required three strikes. After a normal first strike, it received a 90 percent off-center second strike that was uniface (struck against an underlying planchet). It then flipped over and received a third off-center strike, which was also 90 percent off-center, also uniface and directly on top of the second strike.

Pseudo-mules are much more compelling and deceptive when the two obverse or reverse designs are complete. The illustrated 2005 Malaysia 1-sen coin is a pseudo-mule that carries the obverse (hammer die) design on each face. Two steps were necessary to create it.

In the first step, two planchets were placed together in the collar and struck. The top coin was left with a die-struck obverse design and a featureless reverse face. Such an error can occur naturally and is called either a “uniface strike” or a “full indent.” The coin was then flipped over and placed back into the collar on top of a fresh planchet. When the two discs were struck, it left the top coin with a fresh die-struck obverse design on the original featureless surface. The original die-struck obverse face was flattened from where it rested on the planchet during the second strike.

Many similar 1-sen pseudo-mules emerged around this time period and are clearly intentional errors. Several have been erroneously encapsulated by Professional Coin Grading Service as double-obverse mules.

A double-reverse pseudo-mule can be created in the much the same way. One simply uses the bottom member of an in-collar uniface pair. Flip it over, place a fresh planchet on top it, deliver a second strike, and you’ve got two reverse designs (one flattened, of course).

A pseudo-mule doesn’t even require two uniface strikes in sequence. A simpler scenario involves a normal coin flipping over and landing perfectly on top of (or beneath) a fresh planchet. The two discs are then struck together in- or out-of-collar. The increased effective striking pressure generated by two stacked discs is sufficient to obliterate the original design on the face struck directly by one of the dies.

This kind of pseudo-mule error will generate a perfectly centered, flip-over, first-strike brockage on the planchet that rests against it.

A final sequence of events requires only a single strike to be delivered to the planchet that will become the pseudo-mule. In this scenario, a coin with an in-collar, first-strike brockage flips over and lands beneath or on top of a fresh planchet. When the two discs are struck together (in- or out-of-collar), the brockaged coin acts like a die and generates a raised, normally oriented design — a counterbrockage. I have not yet encountered this type of pseudo-mule.

However it’s produced, a pseudo-mule will have the raised design flattened on one face. If struck out-of-collar, it will often assume the cupped shape of an anvil or hammer die cap, with the design on its “working” face grossly expanded and distorted.

Have any domestic pseudo-mules been mistakenly encapsulated as true mules? Possibly. A third encapsulated two-tailed quarter dollar is known, but this one was double struck in-collar, the second time against an unstruck planchet. One face is correspondingly flattened and distorted. While Numismatic Guaranty Corp. claims the coin was struck by two reverse dies, its appearance is equally consistent with that of a two-tailed pseudo-mule produced in a manner described earlier.

Ext. 172.

http://www.coinworld.com/articles/two-headed-two-tailed-pseudo-mules-delight-an/

2011 05 03

Reverse of 2007 silver Eagles

Key clue to variation is u in united

By Erik Martin | May 22, 2011 10:00 a.m.

Article first published in 2011-05-03, Expert Advice section of Coin World

The style of the u in united is one distinct difference between Reverse of 2007, left, and Reverse of 2008, right, American Eagle silver coins. Some Uncirculated 2008-W coins were struck using older reverse dies, creating a variation.

Images courtesy of John Nanney and Harlan J. Berk Ltd.

This is a question regarding the American Eagle silver dollars of 2008, 2009 and 2010 and the reverse side of the coin at the legend united states of america. The u in united has a different shape, unlike the u on the other silver
American Eagles.

Is this an error? I would appreciate knowing the next step in having my coins verified.

Frank Seminara, Citrus Springs, Fl.

Beginning with 2008 strikes, the U.S. Mint began using a slightly modified design on American Eagle 1-ounce silver bullion coins, Uncirculated (with W Mint mark) silver coins and Proof (with W Mint mark) silver coins. However, some of the Uncirculated (often termed as “Burnished Uncirculated” by collectors) 2008-W strikes featured the older font style on the reverse, used on 2007 and prior strikes. The difference was most noticeable on the u in united states of america.

The United States Mint admitted that it released 47,000 Uncirculated 2008-W American Eagle silver coins struck with the older reverse dies. These are referred to in collecting circles as “Reverse of 2007” strikes.

In early January 2008, Mint officials confirmed that style changes, primarily in the lettering for better metal fill, were intentionally made on the obverse and reverse of the Proof, Uncirculated and bullion 2008 American Eagle silver coins. No one outside the Mint was aware of the change until the 2008-W Reverse of 2007 coins began to turn up in the marketplace side by side with coins bearing the updated reverse.

Mint spokesman Michael White said the Mint made the “artistic design changes” while moving from hand-engraving to digital engraving. American Eagle silver coins struck in 2008 to the present feature the newer style lettering on their reverse legends. While use of the older style was an unintended “error” on the part of the Mint, the 2008-W Reverse of 2007 coin is more or less considered a variety rather than an error. Other than the aforementioned 47,000 pieces, Coin World is currently unaware of any other American Eagle coins exhibiting the Reverse of 2007.

Before sending a suspected 2008-W American Eagle, Reverse of 2007 silver coin to a third-party grading service, the collector should determine if the coin is indeed a Reverse of 2007 variation. Here is a quick tutorial:

? The u on the normal reverse (Reverse of 2008) has a spur on the right side of the letter.

? The Reverse of 2007 has a simple bowl-shaped u, without a spur or down-stroke.

Coin World’s Readers Ask department does not accept coins or other items for examination without prior permission from staff member Erik Martin. Readers Ask also does not examine error or variety coins. Materials sent to Readers Ask without prior permission will be returned unexamined. Please address all Readers Ask inquiries to emartin@coinworld.com or call (800) 673-8311, Ext. 274.

http://www.coinworld.com/articles/reverse-of-2007-silver-eagles/

MD-9

Certain error coin production patterns often

mystifying.

By Mike Diamond. | April 30, 2011 10:00 a.m.

Article first published in 2011-05-09, Expert Advice section of Coin World

This Lincoln 1966 cent was struck by a horizontally misaligned obverse (hammer) die. The coin was struck in-collar and the reverse face is perfectly centered.

Image by Mike Diamond

The 20th and 21st centuries are studded with numerous spikes (and drops) in the production of specific error types. These spikes affect numerous categories of die, planchet and striking errors. Some surges in striking errors are easily explained. The year 1966 produced numerous rotated die errors (mostly 90 degrees) among Jefferson 5-cent coins. The vast majority can be traced to a single malfunctioning press. This same year brought us a less easily explained rash of Lincoln cents struck by horizontally misaligned obverse (hammer) dies. The misalignments are unusually severe, and head off in several different directions (see photo of 1966 Lincoln cent).

Lining up a quartet such errors, I was unable to match up the patterns of die scratches. Each coin was clearly struck by a different die pair; how many different presses were involved cannot be ascertained. Equally puzzling is the failure to see a similar error pattern in other denominations struck in 1966. Except for some rare instances, coinage presses are not dedicated to a specific denomination. Once the production totals for one denomination have been satisfied, the dies, collar and feeder assembly are changed to accommodate a different denomination.

Error production patterns confined to a single denomination are actually quite common and can stretch over several years. In the July 12, 2010, “Clearinghouse” column, I reported on a nine-year run of Lincoln cents with faint, oddly positioned clash marks (see photo of 1996 cent here). The clashes all occurred when the hammer die was tilted and horizontally misaligned to a remarkable degree — up to 50 percent. They’re so different from ordinary clash marks that it seems likely the mishaps occurred during installation rather than during a press run. Restricted to the years 1992 to 2000, the current count is 19 die pairs. Again, it’s unclear why the same mishap failed to occur when these presses were switched to other denominations.

An error production pattern can even be confined to a single design sub-type. In the Jan. 3 “Collectors’ Clearinghouse,” I reported on research conducted by Robert “BJ” Neff on tilted die clashes found in 1960-D Lincoln, Small Date cents (and one 1960 Small Date cent). An example of the 1960-D cent is shown here.

A tilted die clash occurs when the hammer die makes direct contact with the anvil die at an angle, leaving a set of reciprocal clash marks at one pole on each die. Such clashes are quite rare — except in this sub-type. At the time of writing, 35 such clashes have been cataloged, with at least 15 waiting in the wings for cataloging.

While examining more than 5,000 Small Date cents from both the Philadelphia and Denver Mints, Neff noticed some other intriguing patterns. Not a single conventional die clash (which produce the familiar “Lincoln in jail” effect) was found. Many of the dies from both Mints were covered by heavy die scratches, regardless of whether clash marks were visible. Die scratches are the product of intentional die abrasion, performed to remove clash marks and other types of superficial damage.

Neff also detected a high frequency of “conflicting dies” (switch-outs). These examples show clash marks on only one face; the opposite die was replaced before the press was restarted. Neff thinks that the presses responsible for the tilted die clashes and other effects were plagued by a number of problems: 1) difficulty in maintaining a horizontally oriented hammer die face, 2) difficulty in maintaining the minimum die clearance necessary to prevent a clash in the case of a planchet misfeed, and 3) an abnormally high rate of complete planchet misfeeds.

Neff thinks it’s possible that a different kind of press was used, or that a standard press was modified for the production of these Small Date cents. Whatever the changes, they didn’t work out very well and the experiment was abandoned.

Neff’s scenario only works if we surmise that the novel press design was used strictly for the small date cents. It also raises the question of why the cent design was modified after the experimental presses were abandoned. Conjecture aside, his evidence at least calls into question the standard explanation for the switch to the Large Date sub-type — a propensity for die chips to develop in digits of the small date.

Further details of Neff’s investigations can be found at www.maddieclashes.com.

http://www.coinworld.com/articles/certain-error-coin-production-patterns-often-/