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Scale Rules
Triangular Rules

To help users place the scales as close to their drawings as possible, makers sometimes placed open divided and chain scales along the sides of a triangular prism. Significant American manufacturers and retailers represented on this page include Darling, Brown & Sharpe of Providence, R.I.; James W. Queen & Company of Philadelphia; Keuffel & Esser of New York; and the Eugene Dietzgen Company of Chicago.