Diwa № 601-1

The Dansk Industri for Waterpasser A/S (DIWA) manufacturing company created the № 601-1 as a promotional item sold for other companies to pass on with their branding. It is an all plastic pocket sized rule.

601-1

Type	Slide Rule
Manufacturer	Dansk Industri for Waterpasser A/S (DIWA)
Calculator
Precision	2 to 3 significant digits
Display type	Analogue scales, sliding cursor (multiple hairlines)
Programming
Other
Dimensions	5.75" (14.55cm) length

Overview

The 601-1 was a promotional rule sold to many companies and stamped with many brand names. It is a simplex (one sided) pocket sized rule that was convenient for quick calculations, including multiplication, squares, trig functions, and common logarithms. included on the cursor are extra hairlines to assist with calculating conversions between common units, as well as easily calculating the area of circles with a given diameter. Also included are scale extensions on both ends of the rule which allow for calculations past the index in certain cases. As with most linear slide rules, these calculations could be chained together to compute relatively complex equations quickly and fairly accurately. The primary limiting factor of this rule is its size, which limits the amount of accuracy of setting scales against one another.

Scales

The 601-1 is a simplex rule with a total of nine calculating scales, with six rules easily accessible on the face of the rule. The final three scales lie on the back of the slide, and can be accessed with a window on the back of the rule that aligns with the right index of the primary scales. All reverse scales are keyed to the C scale.

Layout

The layout is a common Rietz pattern, and is an archetypal representation of that pattern.

Front

K A (B CI C) D L

Back

(S ST T)