Dietzgen / Gilson         The Binary Slide Rule   1797B

  • This rule was made by Gilson but sold by other companies also, including Dietzgen, POST and others.

  • Most famous circular slide rule, and most useful in the USA.

  • Include fractional converter and very precision trigonmetric function.

  • About twice precision compared to the 25cm type rules:
    Ex. Binary scale shows 1.005~9.98, while C scale of 25cm type shows 1.01~9.95.