The Heuer Calculator chronograph incorporates a simple slide rule into the case and its rotating bezel. The Calculator’s slide rule is comprised of the two fundamental slide rule scales – the C scale and the D scale. These are identical logarithmic scales, with the cycle 1 to 10, commonly used for multiplication and division.
In addition to the usual slide rule scales, the Calculator has a broad range of unit conversion marks on the inner bezel. The marks can be used to convert the following types of units:
- nautical miles / statutory miles / kilometers / yards / feet / inches
- knots / miles per hour / kilometers per hour / miles per minute
- imperial gallons / U.S. gallons
- pounds / kilograms
Diagram V on page 7 of the instruction booklet provides a good overview of the unit conversion marks used on the Calculator chronograph.
The instructions for operation of the Heuer Calculator slide rule will be useful for other circular slide rules that are incorporated into watches and chronographs, which include the C and D scales.
We also include a high resolution PDF of the instruction booklet.
