The A-to-Z of Slide Rules

This is a fairly general A-to-Z of slide rules. It is designed for people who have never used a slide rule before or who have used one in the past but largely forgotten what to do. The sections are arranged in alphabetical order.

If you are a complete novice then I suggest that you go first to the "Beginners Start Here" section and then work through the individual sections of the A-to-Z. After that you can tackle the book "Teach Yourself the Slide Rule" or read some of the on-line instruction manuals.

Whilst this A-to-Z tries to cover a wide range of scales, it is impossible to cover all possible types of scales or all types of rules. If you have a scale that you cannot identify then have a look at some of the sites mentioned on the resources page. If you cannot find what you want there there, post a question on the slide rule forum ( where someone will, almost certainly, be able to be able to help you. (A word of warning - some of the participants have a rather unusual sense of humour!).

The descriptions below are of two main types: descriptions of general purpose scales which you will find on many rules and descriptions of rules for special functions. In the latter case I consider how typical calculations can be performed using a range of special purpose slide rules but only consider any special scales or gauge marks. The aim is to cover enough rules so that if the actual rule you have is not included a similar one will be, which will enable you work out how to use it. (For me part of  the fun of slide rule collecting is working out how to use new rules.) Much of my effort over the coming months will be to add more information on these special rules some of which is at present covered by special purpose rules in my collection. The sections are identified by the yellow background.




Accuracy How to check the accuracy of your rule.
Addiator A device for addition/subtraction sometimes found on the back of slide rules.
Business rules See Commercial rules
Circular slide rules (see Concise)
Coggeshal rules See timber rules
Commercial rules Six rules used as examples
Concise 28 A common circular rule.
Cubes and cube roots Uses of K scales
Cursor (indicator) Covers use of multi-line cursors
Cylindrical slide rules (see Otis King)
Darmstadt (see standard scale configurations)
Decimal point How to fix the position of the decimal point.
Division (see Multiplication and Division)
EasrR sewer flow rule A hydraulic rule for sewer flow.
Electrical Faber Castell, Thornton PIC, W&G and Graphoplex rules are used as examples.
Electronic Graphoplex and Pickett rules are used as examples.
Exponentiation The use of log-log scales
Financial rules See commercial rules
Fowler A well known circular rule
Gauge points Explains the use of the p and other symbols.
Gauging Calculating the volume of casks when full or partly full.
History A very brief history of slide rules
Hydraulics (See EasyR, Tarrant and Mears)
Hyperbolic functions Pickett and Keuffel & Esser rules are used as examples.
Indicator See cursor
Logarithms (background)
Logarithms (base 10)
Mannheim (see standard scale configurations)
Mears hydraulics rule A circular rule for pipe and channel flow.
Multiplication and Division Shows use of C, D, CI, CF and DF scales.
Non-linear rules
Otis King A well known cylindrical rule.
Pocket watch slide rules (see Fowler)
Raising to a power (see exponentiation)
Reading the scales How to read the scale graduations.
Roots and powers - squares and square roots Basic use of A and B scales
Roots and powers - cubes and cube roots Basic use of K scale
Roots and powers - calculation involving Multiplication and division of numbers involving squares and square roots.
Rietz (see standard scale configurations)
Scales How to identify the scales on a rule and how to read them.
Sin(e) (see trigonometric calculations)
Squares and square roots The use of the A and B scales.
Standard scale configurations
Stator See stock
Stock (stator)
Tan(gent) (see trigonometric calculations)
Tarrant hydraulics slide rule. For pipes and channels.
Timber rules Instructions on a common early type of rule.
Trigonometric calculations : scales on stock (stator) Found on many rules from the USA.
Trigonometric calculations : scales on front of slide Found on many rules from Europe.
Trigonometric calculations : scales on back of slide Found on many early rules from all over the world.
Trigonometric calculations : scales on Thornton/P.I.C. rules Patented and only found on rules from this maker.
Trigonometric scales - comparison Comparison of different methods of presenting scales.
Trigonometric calculations - gauge points for small angles Common on European rules
Ullaging (see gauging)