PART V. Planchet Errors:

Bi-metallic Errors:

Struck Outer Rings

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.

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 bi-metallic error allows in-depth study of how the ring and core interlock and join together.

A 2006 Great Britain two pound Technology coin with no core present.

On this bi-metallic error the core is grooved (see ‘struck core’) and would penetrate the inner portion of the outer ring.

A 1988 Italian 500 lire coin with no core present.

Here the inner portion of the ring is keyed with three crimped slots. The center image is a close-up of one of these crimps at the 6 clock position (just above the designer’s name). These keys penetrate the core when both components are joined together.