Definition: A coin struck inside a collar whose diameter is wider than normal. This rare error is subtle and is often
only detected when an otherwise normal-looking coin gets stuck in a plastic storage tube or won’t fit in its designated hole inside a cardboard Dansco album.
An abnormally wide collar can arise in several ways:
- A collar intended for a different (perhaps foreign) denomination is inadvertently installed in a press.
- A smooth-faced collar is mistakenly machined too wide.
- A reeded collar is widened beyond normal tolerances through the use of an incorrect ridged broach that is
hammered into the collar opening.
- A normal collar is not replaced in a timely manner and widens due to prolonged use.
- The presence of three or more vertical collar cracks allows the collar to expand.The last two circumstances are probably the most common causes of this error.
This 1918 cent was struck in a collar that expanded due to the presence of four vertical collar cracks. Its diameter
measures 19.45 mm instead of the normal 19.05 mm.
The above 1999-P dime was struck in an abnormally wide collar. The diameter of this dime measures 18.24 mm instead of the normal 17.91 mm. It’s likely that the collar expanded due to the relentless pounding involved in restraining hundreds of thousands of planchets. The edge is slightly convex in vertical cross-section, which is consistent with this scenario. This dime also shows a case of surface film transfer on the obverse face. This type of error occurs when the preceding coin is double struck with movement between strikes. If either the coin or the die is grimy, a shadow image of the first strike is transferred to the die face and then transferred back to the next planchet.
For more information on wide collar errors see the May 17, 2010 Coin World.