(1965) Dime Pattern - RB-4005, INCO

Coin Details

Description

A second-phase INCO experimental clad dime bearing a distinct alloy formulation from RB-4000. The RB-4005 composition represents one of several incremental adjustments tested on Roosevelt dime dies during 1965, after the initial round of INCO experiments in 1964 had narrowed the field of candidate alloys. By the time these pieces were produced, the Coinage Act of 1965 had already established copper-nickel clad as the legal standard for dimes and quarters, but the precise alloy ratios remained subject to ongoing refinement. INCO, as the dominant North American nickel producer, had a substantial financial stake in ensuring that whatever composition the Mint adopted would consume significant quantities of nickel. The company's metallurgists worked closely with Mint technical staff to optimize the alloy for vending machine acceptance, wear resistance, and visual similarity to the outgoing silver coinage. RB-4005 was struck at the Medallic Art Company using standard Roosevelt dime dies, producing a coin that would be visually indistinguishable from a regular dime to most observers despite its experimental composition. The physical characteristics of each alloy variant were meticulously documented, including conductivity, specific gravity, and hardness measurements that determined compatibility with existing coin-operated mechanisms.

Rarity Notes

R-7 to R-8. Very few specimens are known outside institutional holdings. The 1965 INCO dime patterns are considerably scarcer than the more extensively studied 1964 series.

Cross References

Research Blank RB-4005 (Gould/INCO experimental series)