This 24-page booklet was received with 1981.0922.12. Its citation information is: Maurice L. Hartung, Dial Rule Circular Slide Rule: Your Model No. 101-C Instruction Manual (Chicago & Alhambra, Calif.: Pickett & Eckel, Inc., 1957). The back is marked: PRINTED IN U.S.A.; FORM M-18. The Pickett logo on the front cover was used between 1958 and 1962.
The manual provides instructions and processes for the C and CI scales, multiplication, division, combined operations, the A and Af scales (for square roots), logarithms and adding fractions, the LL scale, the DS and DT scales (for drill sizes and double depth of threads), the M scale (for metric conversions), and the S, ST, and T scales (for trigonometry). There are 24 problems and answers on the back page.
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