(1964-65) Blank Pattern - RB-6110, INCO

Coin Details

Description

Experimental blank planchet RB-6110, the second entry in the RB-61xx subseries of INCO experimental compositions. Building on the baseline established by RB-6100, this blank tests a variant formulation within the same alloy family, exploring how specific compositional modifications affect the planchet's critical properties. The RB-61xx subseries, with its closely spaced entries from RB-6100 through RB-6140, documents an intensive investigation of a particular metallurgical approach that was considered promising enough to warrant detailed parametric study. The blank planchet format continued to serve as the primary vehicle for alloy evaluation at this stage, with each composition subjected to a battery of standardized tests: weight measurement to verify density compatibility with existing coin specifications, electromagnetic testing to assess vending machine acceptance, accelerated corrosion testing to predict circulation durability, and cross-sectional microscopy to evaluate the integrity of the clad bond. The cumulative results from these tests, applied across all compositions in the RB-61xx series, built the empirical foundation for INCO's alloy recommendations.

Rarity Notes

R-7 to R-8. Very rare experimental specimen from the RB-61xx composition family.

Cross References

RB-6110 (Robinson-Breen catalog). INCO experimental blank planchet series, RB-61xx group, 1964-65.