(1964-65) Blank Pattern - RB-6010, INCO

Coin Details

Description

Experimental blank planchet RB-6010, the second documented entry in the RB-6xxx INCO series. The ten-unit spacing from RB-6000 mirrors the wider intervals observed in the RB-54xx subseries, suggesting that the RB-6xxx group employed a similarly exploratory approach, testing broadly spaced compositions to survey a wide range of alloy possibilities. The physical characteristics of RB-6010 — its diameter, thickness, weight, and edge appearance — carry particular diagnostic value, as they may reveal whether the RB-6xxx blanks were intended for a specific denomination or were generalized test pieces evaluated independently of any particular coin format. INCO's metallurgists understood that an alloy's performance could vary significantly with planchet geometry: a composition that worked well in a thick half-dollar blank might perform poorly when rolled to the thinness required for a dime planchet. By testing compositions across multiple size formats, the program could identify alloys with robust performance characteristics that would tolerate the manufacturing variations inherent in large-scale coinage production.

Rarity Notes

R-7 to R-8. Surviving RB-6xxx blanks are among the rarest artifacts of the INCO experimental program.

Cross References

RB-6010 (Robinson-Breen catalog). INCO experimental blank planchet series, RB-6xxx group, 1964-65.