Search Results for: off center

Retained Cuds: Horizontal Offset

PART IV. Die Errors:

Cuds:

Retained Cuds (with horizontal offset)

Definition: A retained cud is a piece of a die that breaks off completely but is held in place. Retained cuds of the anvil die are held in place by the collar while retained cuds of the hammer die are presumably held in place by the bolts that secure the die in its recess. Retained cuds of the hammer die are much rarer, as die fragments tend to fall out with the assistance of gravity.

In order to diagnose a retained cud, one needs to see vertical displacement and/or horizontal offset. Vertical displacement simply means that the die fragment sinks in below the level of the die face, leaving the coin’s design sitting on a corresponding plateau. Horizontal offset means that the fragment slides along the break, leaving contiguous parts of the design out of alignment with each other on either side of the break.

Depicted below are close up images of a Columbia one centavo with a retained cud. While there is more going on here in addition to the horizontal offset, it is our focus for this illustration.

Irregular Planchet Off Metal

PART V. Planchet Errors:

Irregular Planchets:

Scraps / Fragments:

Off-metal

Definition: Occasionally fragments of metal are struck that have a composition different from the coin whose design it carries. Sometimes the composition of these fragments matches those of another denomination. In other cases the composition is quite exotic.

This undated Roosevelt dime has been struck on a piece of copper scrap metal.

Images are courtesy of Heritage Auctions.

Design Scraped Off Ablation First Strike

PART VI. Striking Errors:

Design Ablation Error:

On First Strike

Definition: The die-struck design on the surface of a coin is scraped off by lateral (horizontal) die movement.

This 2001-D Lincoln cent exhibits a design ablation error on the first strike. The hammer die made initial contact with the planchet in a centered position but settled in a misaligned position. During its lateral shift toward the northeast, the hammer die continued its descent through the body of the coin. The completion of the downstroke amounted to no more than a fraction of a millimeter of vertical distance. The combination of movements (vertical and horizontal) left a crescentic “zone of ablation” on the left side of the coin. All design elements that were generated by the initial, centered impact of the hammer die were completely scraped off. The zone of ablation is filled with fine parallel striations and shows a very gentle downward slope that begins at the original design rim.

After reaching the lowest point of its downstroke, the hammer die lurched toward the southwest, dragging itself through the newly-struck design. This left the design grotesquely distorted. This form of distortion is classified as a form of machine doubling known as slide doubling. Design ablation errors that occur on the first strike are usually associated with severe slide doubling.

Design ablation errors on the first strike are usually misidentified as simple misaligned die errors.

Design Scraped Off Ablation Second Strike

PART VI. Striking Errors:

Design Ablation Error:On Second Strike

Definition: The die-struck design on the surface of a coin is scraped off by lateral (horizontal) die movement. This can occur on a first or second strike.

This quadruple-struck 2000-D Lincoln cent was struck with inverted dies (reverse die acting as hammer die). The first strike was normal. The third and fourth strikes were received in tandem as the coin straddled two adjacent striking chambers (a saddle strike). The second strike was off-center, uniface, and incorporates a design ablation error.

During the second strike, the impact of the hammer die on the reverse face was relatively weak, even though the aggregate thickness it confronted was doubled by the presence of an an underlying planchet. After making light contact with the surface of the coin, the hammer die shifted a considerable distance toward 12:00 (reverse clock position). As the die moved northward, it completely scraped off the first-strike design elements and whatever second strike design elements were generated during the initial impact. All that is left is a series of fine parallel striations that expose a little bit of the zinc core.

This is the only known example of a design ablation error on the second strike.

Broadstrike: Uncentered

PART VI. Striking Errors:

Broadstrike:

Uncentered

Definition: When a planchet is poorly centered and then struck out of collar, it ends up as either an off-center strike or an uncentered broadstrike. To qualify as an uncentered broadstrike, the design must be fully present on both faces. If the design is cut off at the edge on one or both faces, it is an off-center strike.

Various factors determine whether a poorly centered planchet ends up with some of the design cut off at the edge. One factor is, of course, how far to one side the planchet settles. Another factor is the strength of the dies’ impact. A very strong impact will cause significant expansion of the planchet and turn what would ordinarily be an off-center strike into a an uncentered broadstrike. The third factor is the coin’s design. If peripheral lettering is separated from the design rim by a significant gap, it has a greater chance of ending up as an uncentered broadstrike, all other things being equal. Likewise, if the design rim is quite broad, the coin once again stands a good chance of ending up as an uncentered broadstrike, if we control for planchet positioning and striking pressure.

The above images show an uncentered broadstrike that occurred on a 1999(P) Lincoln cent.

Bi-metallic Misaligned Center Hole

PART V. Planchet Errors:

Bi-metallic Errors:

Misaligned Center Hole

Definition: Bi-metallic error coins are restricted to foreign countries. These coins may experience any of the many types of striking errors listed in the Error-Variety Ready Reference however, one must understand we are dealing with two components, a ring & a core. Any number of exotic possibilities or combinations of die varieties, die errors, planchet errors & striking errors can be found on bi-metallic coinage.

Either the punch or the solid ring planchet was misaligned when the disc was pierced. The core itself appears misaligned only because the center hole is off-set.

Two specimens are shown.
A 1995 Columbia 500 pesos with center hole misaligned.

A 1996 Canadian polar bear two dollars. The center hole is clearly misaligned.

Rim-Restricted First Strike

Part VI. Striking Errors:

Weak Strikes:

Rim-Restricted First Strike

Definition: A weak strike caused by insufficient die approximation in which the dies are so far apart at their closest approach that they only manage to contact the planchet’s proto-rim. This error can appear on centered planchets and off-center planchets.

The dies that struck this 1999 Pennsylvania quarter were so far apart that they only managed to strike the planchet’s proto-rim. This created a halo of design on both faces while leaving the center of the coin unmarked. Since the inward slope of a strongly developed proto-rim can extend further into the planchet than the design rim, it is possible to get a rim-restricted first strike on a perfectly centered planchet.

This dime was struck approximately 70% off center by excessively spaced dies. There is a faint trace of Roosevelt’s throat in the field. Otherwise, obverse design elements are restricted to the proto-rim. These include his lip, chin, and back of his neck.. Reverse design elements appear exclusively on the proto-rim and include portions of the flame and several olive leaves. Interestingly, the planchet is pristine, having avoided all tumbling marks that are ordinarily picked up in the annealing drum, chemical rinse bath, riddlers, and other sources of planchet-to-planchet contact.

This dime received two off-center strikes. It’s not clear whether it is a saddle (tandem) strike. The off-center strike that is die-struck on both faces is very weak. In the obverse field, there is a faint trace of Roosevelt’s forehead and crown. A more strongly struck impression of his brow appears on the proto-rim. On the reverse, the first three letters of PLURIBUS appears on the proto-rim, with no design elements visible in the field. The other off-center strike is well-struck, in part because a previously-struck dime was taking up any excess space that may have existed (generating a “mirror” brockage of the obverse design on the reverse face).

Weak Strikes

PART VI. Striking Errors:

Weak (Low Pressure) Strikes

Definition: A weak strike results from two proximate causes, inadequate ram pressure or insufficient die approximation (excessive minimum die clearance). Ram pressure is the tonnage applied to a planchet of normal thickness. Insufficient die approximation refers to the minimum approach the dies make to each other in the absence of a planchet. In many cases it is difficult or impossible to assign proximate cause. However, when a weak strike is accompanied by another error, or a weak strike progression can be assembled, the most common proximate cause appears to be insufficient die approximation. The dies simply don’t approach each other closely enough to leave a strong impression.

Ultimate cause is virtually impossible to determine. A weak strike could be due to a loose or cracked press frame, a loose or broken knuckle joint, a mistimed anvil or hammer die, a broken cam associated with either die, a jam-up in the guts of the press, a jam-up associated with an adjacent die pair, a broken circuit breaker, or simply dies that have fallen out of adjustment. A weakly struck coin could also be a test piece, otherwise known as a “die adjustment strike” or a “die trial”. Many weak strikes are labeled as such. But unless you were there the moment it was struck, there is no way to know. Therefore the terms “die trial”, “die adjustment strike”, “test piece”, and “set-up piece” should be abandoned.

Most, if not all weak strikes available in the marketplace appear to be the result of spontaneous equipment malfunction. The evidence for this is abundant and manifold.

These errors are far too abundant to represent escapees from a test run. Test strikes are supposed to be set aside and consigned to the furnace for melting. You wouldn’t expect many coins to escape this fate.
If these were test pieces, then you’d expect the greatest number of weak strikes to involve the denomination that is produced in greatest abundance – cents. However, weak strikes occur most frequently in dimes. That’s what you’d expect of weakness caused by spontaneous equipment malfunction. Dies that strike thin planchets have a very narrowly constrained minimum die clearance. If the clearance grows just a little bit, the strike will be weak. If the clearance shrinks even slightly, the dies are likely to clash. Thicker denominations have a much more generous clearance range. It is among these denominations that you’d expect to find fewer weak strikes, and this is indeed the case.
Weak strikes can be found in association with a wide range of errors – double strikes, triple strikes, saddle strikes, misaligned die errors, clashed dies, indents, partial brockages, full brockages, struck-through errors, etc. Given how rare escaped test pieces are projected to be, multi-error test pieces should be as rare as unicorns.
On multi-struck coins, a weak strike can immediately follow a strong strike and a strong strike can immediately follow a weak strike. Such rapid changes in die clearance (or ram pressure) would not be expected in a test run.
Weak strike progressions can move in either direction – from weak to strong or from strong to weak. Such a progression can also show an erratic pattern of strengthening and weakening. That’s not what you’d expect of a test run.
On saddle strikes, one off-center strike can be strong and the other weak. With respect to saddle strikes on previously-struck coins, the first strike can be weak while the two off-center strikes can be strong. The reverse situation has also been recorded. A weak first strike can then receive a saddle strike in which one of the off-center strikes is weak and the other is strong. None of these patterns is consistent with a test run scenario.

Weak strikes are sometimes confused with grease strikes – coins that are struck through a heavy layer of compacted die fill. It’s actually quite easy to tell the two errors apart.

A weak strike will show a poorly developed or absent design rim. A grease strike will show a very well-developed design rim.
A weak strike will retain some, most, or all of the planchet’s original proto-rim. The proto-rim is erased in a grease strike.
A weak strike will retain the beveled rim/edge junction of the planchet. The bevel will be lost in a grease strike.
The edge will be weakly struck and relatively narrow in a weak strike. The edge will be tall and vertical in a grease strike.
Reeding will be weak or absent in a weak strike. Reeding will be very strong in a grease strike.
In a weak strike, extent and pattern of weakness will be essentially the same on both faces. Uneven weakness is a hallmark of most grease strikes.

The photo below shows a weakly-struck 2007 Montana quarter. It was struck on a Schuler press, a model that doesn’t even require ram pressure and die clearance to be adjusted by means of a test run. The design rim is fairly well formed because state quarter dies have a relatively flat die face (very little die convexity).

Shown below is a 1983-D 5-cent coin with a weak second strike delivered by a rotated (25 degrees) and misaligned (26%) hammer die.

This quarter dollar was struck three times by the same die pair. The first strike was normal while the second was 40% off-center and exceedingly weak. The third strike was 75% off center and forcefully delivered. This specimen also illustrates the self-correcting nature of some malfunctions responsible for weak strikes.

This 2008-P Andrew Jackson dollar coin did not receive a full strike. Insufficient ram pressure (applied tonnage) or insufficient die approximation are the culprit in this case. This error is often erroneously called “a die adjustment strike”.

Images are courtesy of Heritage Auctions

Mulitple Strikes Flip Over

PART VI. Striking Errors:

Multiple strikes:

Flipover Double and Multi-Strikes

Definition: Most multi-strikes show the same face struck repeatedly. Coins that flip over between strikes are rarer.

The 1935 Lincoln cent shown below is an in-collar, flipover double strike. After a normal first strike, the coin flipped over and landed back inside the collar. It was then struck a second time.

The 2000 Lincoln cent shown below was first struck off-center. It then flipped over and was struck a second time
even farther off-center. The second strike is uniface (struck against another planchet).

Index Of Completed Entries

Index entries are a mixture of higher-level and lower-level entries. Lower-level entries are often inserted into the index in alphabetical order and may therefore be separated from the higher-level entry they fall under in the Checklist.