Collar Clash Error Coins are a phenomenon that, until relatively recent times, was almost wholly restricted to the hammer die.
the outer edge of the obverse design rim from 1:30 to 5:00. The serrations are
out-of-register with the coin’s reeding.
A typical Collar Clash Error Coins occur when a temporarily misaligned hammer die collides with the top of the collar and scrapes down along the collar’s working face. In the case of reeded issues, a set of parallel grooves are carved into the die neck and the outer margin of the die’s rim gutter. These grooves appear as a set of serrations along the outer edge of the coin’s design rim.
Collar clash is almost impossible to recognize in plain-edge issues owing to the lack of serrations.
Shown here is a 1983-P half dollar with a well-developed case of collar clash along the right side of the design rim. This specimen is somewhat unusual in that the serrations are half a reed out-of-register with the reeding on the coin’s edge. This would indicate that the die or the collar rotated slightly sometime after the clash. It’s possible that the clash loosened one of these press components.
Collar clash involving the anvil die involves a very different mechanism owing to the fact that the neck of the anvil die is surrounded by the collar. In order to pick up a set of grooves, the anvil die neck has to grind up and down against the collar’s working face or has to be pushed violently to one side so that it’s driven into the ridges.
Collar clash affecting the anvil die is virtually unknown among coins struck with the traditional die setup (reverse die as anvil die). The only example I know of appears on the illustrated off-center dime.
As with any off-center coin, the collar clash is expressed as a set of transverse grooves that occupy the slide zone, which are located below the word ONE in this specimen. It seems that the anvil die collar clash was just part of a more widespread malfunction.
The planchet shows a highly unusual form of pre-strike damage in the form of three equidistant indentations in the planchet’s edge that respectively lie at 9:00, 12:00, and 3:00 (obverse clock position).
A rim burr was also gouged up from planchet’s obverse proto-rim next to the off-center strike (Coin World, October 20, 2023).
Pre-strike damage along the edge of the coin suggests a broader malfunction.
Collar clash affecting the anvil die became more common once the Mint switched over to the high-speed Schuler press. The Schuler press is associated with the inverted die setup (obverse die as anvil die). It is also associated with a horizontal striking mechanism. In other words, the hammer and anvil dies are horizontally oriented instead of vertically oriented.
Until recently, I had assumed that all Schuler press models used by the U.S. Mint employed horizontally configured dies. However, on August 16, 2025, Pete Apple posted information on Joe Cronin’s Facebook group indicating that from 2000 to 2003 at least four Schuler press models used in the Philadelphia mint employed vertically oriented dies (facebook.com/groups/281634085880277).
dime shows anvil die collar clash.
Shown above is a 2022-P dime with collar clash affecting the anvil (obverse) die. I am certain of this because, by 2002, nearly all business strike coins were struck with the inverted setup. A few coins struck with the traditional setup are known past 2001, but these peter out after 2007. The one exception is a 2021-P half dollar struck with the traditional setup (Coin World September 30, 2024).
I strongly suspect that the increase in cases of anvil die collar clash on 21 st century dimes and quarter dollars is connected to the use of horizontally oriented dies. It may be something as simple as gravity causing a loose anvil die to sag against the collar’s working face or a loose collar falling against the anvil die neck. In either case, and depending on press design, reciprocating movements of the anvil die or collar would gradually carve a set of grooves into the anvil die neck and rim gutter.
It stands to reason that an increase in the frequency of anvil die collar clash raises the odds of finding coins with bifacial (two-sided) collar clash. And yet, I’ve only found a few coins or press runs in which both dies picked up collar clash.
Virginia quarter dollar. .
I first noticed bifacial collar clash among a group of 2000-P Virginia quarter dollars produced by a single malfunctioning press that produced striking errors that fall into five categories:
(1) major horizontal misalignments of the hammer (reverse) die
(2) horizontal misalignments of the anvil die (both major and minor),
(3) major bifacial (dual) misalignments (4 known),
(4) off-center strikes, which are usually associated with a minor misalignment of the hammer die, and
(5) uncentered broadstrikes (2 known).
These errors are distributed more or less randomly among 9 die stages (Prime, A-H).
Bifacial collar clash appears on these errors at least as early as Die Stage A. Shown here is one of the four known dual misalignments.
The anvil (obverse) die’s collar clash is detectable from 9:00 to 1:00. The hammer (reverse) die’s collar clash is even longer, although the serrations are less clear. It runs clockwise from 10:00 to 4:00.
A fixed point of contact between die neck and collar is unlikely to produce a collar clash longer than the 120 arc degrees seen on the obverse face.
The 180 degree arc seen on the reverse face suggests a moving point of contact.
I’ve seen one dime with collar clash at opposite poles on the same face, denoting a significant degree of instability in the location of the contact points. It’s clear that the two arcs of collar clash on these Virginia quarters are not aligned in vertical space.
From that it’s probably safe to conclude that there’s no direct causal relationship between the two episodes of collar/die contact.
A second case of bifacial collar clash is seen on a broadstruck 1999-D Georgia quarter dollar. On the obverse, the serrations run clockwise from 11:00 to 1:30. On the reverse, the serrations run clockwise from 5:30 to 7:30.
Unlike the Virginia quarter, the two serrated arcs do partly overlap in vertical space.
It’s not clear whether this is coincidental or whether there was some causal connection between the two collar clashes.
Since this coin shows no signs of collar contact, it’s impossible to determine whether it was struck with the traditional die setup or the inverted setup.
Both arrangements were in wide use by 1999. However, since anvil die clash is almost unknown among coins struck with the traditional setup, it stands to reason that this quarter dollar was struck with the inverted setup.
The post Bifacial Collar Clash Error Coins Seldom Encountered appeared first on CoinWeek: Rare Coin, Currency, and Bullion News for Collectors.
