Bi Metallic Errors

Error-Variety Ready Reference

Bi-metallic Errors

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.

	Misaligned Cores A misaligned core may occur for various reasons. Three scenarios are listed below: (1) Center hole of ring too small, grossly misshapen or both, (too small or too misshapen to accommodate a correct fit for a correctly-sized core). (2) An incorrectly sized core which will not fit into a normal sized center hole of the ring. (3) An improperly inserted core due to malfunctioning equipment or inattentive workers, (even when both components are without flaw). Three images below include obverse face (left), low angle view of edge (center), & reverse face of Sri Lankin 10 Rupees having a misaligned core.

2007 Slovenian two euro with grossly misaligned core.

2005 Kenyan 5 Shillings with grossly misaligned core.

	Misaligned Center Hole Either the punch or the solid ring planchet was misaligned when the disc was peirced. The core itself appears misaligned only because the center hole is off-set.
	1996 Canadian polar bear two dollars. The center hole is clearly misaligned.

1995 Columbian 500 pesos with center hole misaligned.

Double Punched center hole

2004 Columbian 500 pesos. The center hole has clearly been double punched.

	Incomplete Second Punch
	1996 Canadian polar bear two dollars. While the center hole is clearly misaligned, there was an unsuccessful attempt to punch the ring a second time. Second punch scaring is evident on both obverse & reverse face (black arrows indicate second punch scaring).

	Struck Outer Rings An outer ring struck without a core will expand inward. This results in design elements that are normally restricted to the core appearing on the inner portion of the abnormally wide ring. This type of error allows in-depth study of how the ring and core interlock and join together. Three images below include obverse face (left), low angle view of edge (center), & reverse face of 2006 Great Britain two pound Technology coin with no core present.


	1988 Italian 500 lire coin with no core present.

	Struck Core A core enters the striking chamber without having been joined or mated with its ring. The nature of this error allows a complete study as to the method of interlock joining the ring and core together. Obverse face (left), low angle view of edge (center), & reverse face (right) of Great Britain two pound Technology core. Note the groove along the edge of the core. The groove accommodates metal from the ring that is extruded into it. At the same time, the metal on either side of the groove is designed to penetrate the innermost portion of the outer ring when joined.

Mexican one pesos struck on core.

	Struck Core from another country A mind blower, these are an extremely rare encounter. The example shown below is from Iceland which has never used bi-metallic coinage during its entire history. Obverse face (left), low angle view of edge (center), & reverse face (right) of Icelandic 10 kronor. (Center image is a comparison with a normal 10 kronor. The groove around the edge is quite obvious).

	Another mind blower. While Great Britain has bi-metallic coinage, this magnetic nickel core was destined for a one euro denomination bi-metallic coin (country unknown). This core found its way into the striking chamber for a 2007 British one pound Gateshead coin. Obverse face (left), low angle view of edge (center), & reverse face (right) of British one pound Gateshead struck on a one euro core. (Center image clearly indicates groove around the edge).

	Wrong Ring Occurs when a normal core is joined with a wrong ring. These errors are unequivocally rare.
	Two pound 2006 Isambard Brunnel from Great Britain. The ring is is stongly attracted to a magnet. (Either elemental nickel or steel composition).

Two pound Technology from Great Britain. Ring is strongly attracted to a magnet (steel ring). The ring also has a misaligned center hole. The ring is much thinner than the core resulting in the near incomplete absence of design transfer on either face of the ring.

Two pound 2007 Gun Powder Plot from Great Britain with wrong ring. The ring also has a misaligned center hole. The ring is thinner than the core resulting in the absence of some design transfer on either face of the ring.

	Ring accidentally punched from solid coin Exotic and extremely rare encounter
	An incredible occurrence; a previously struck Hong Kong one dollar coin (solid) was center hole punched creating a morphed outer ring. This ring was then joined with a core and struck by two pound technology dies from Great Britain.

	Wrong Core inserted An incorrect core is wrongly inserted into the ring center hole. Occurrences are quite rare.
	2006 two pound technology from Great Britain having a steel core inserted before strike. (Core is strongly attracted to a magnet).

2005 Chilean 100 Pesos having an aluminum core inserted before strike.

	Incomplete Trilaminar Core Two euro denomination bi-metallic coins have a trilaminar core. The core is a disc composed of elemental nickel sandwiched by a thin layer of nordic gold on either face.
	2002 two euro from Germany missing both the center nickel and outer trilaminar layer on the obverse face. Examples are known from various european countries.

Bi-metallic planchet struck with Wrong Bi-metallic Design

A bi-metallic planchet enters the striking chamber fitted with the wrong design dies.

2005 Chilean 100 pesos struck with wrong bi-metallic planchet design (ring & core).

	Bi-metallic planchet struck by solid Denomination Dies An unstruck bi-metallic planchet enters the striking chamber meant for solid planchets.
	2006 Chilean 10 pesos on 100 pesos bi-metallic planchet.

2005 Chilean 50 pesos struck on a multi sided bi-metallic planchet. While Chile has bi-metallic coins, none are multi sided. Side by side comparison images of obverse & reverse faces with a normal solid, multi sided 50 pesos is shown. Only the one, five & 50 pesos coins from Chile are currently multi sided.

2005 Chilean 50 pesos struck on a multi sided bi-metallic planchet. While Chile has bi-metallic coins, none are multi sided. Only the 100 and 500 Chilean pesos coins are currently bi-metallic.