Slide Ruling Know your A, B, Cs and DsIntroducing the Slide Rule 2013 - Ferrick GrayKanticle of BeingPickett

PPT1Introduction

The slide rule is a simple tool.

To use the slide rule with confidence, you must have a clear understanding of its operation.

The ends of the slide rule should be held between the thumb and forefinger. Holding the rule at the center will hinder the movement of the slider.

The slide rule consists of three parts:

The body (stock or stator);The slide (slider); andThe cursor or indicator with its hairline.

The scales on the body are arranged to work together in solving problems.

Each scale is named by a letter or symbol.

The hairline on the indicator is used to help read the scales and adjust the slider.

The General Idea

The C and D scales are the most important and their basic use is to multiply numbers.

2 x 3 = 6

The cursor can be moved to easily find other products with the same factor.

2 x 4 = 8

Graduations

Each mark on a scale is called a graduation.

The left index is labeled with 1.

The right index is labeled with a 1.

The ten marked numbers are called primary graduations.

Primary graduations get closer together as we move left to right.

This is a non-uniform scale.

The D Scale

The marks between the primary graduations are called secondary graduations.

There are more secondary graduations between some primary graduations than others.

Each division between primary graduations is read as though they are divided into tenths.The D Scale

Example readings between the primary 1 and primary 2 with the left index representing 1.

Example readings between the primary 3 and primary 4 with the left index representing 1.

Example readings between the primary 1 and primary 2 with the left index representing 10.

Example readings between the primary 3 and primary 4 with the left index representing 10.

Between the secondary 1 and the secondary 2, there are tertiary graduations.

These allow more accurate readings.

Example reading between primary 1 and secondary 1.1; secondary 1.4 and 1.5 with the left index representing 1.

Example reading between primary 1 and secondary 1.1; secondary 1.4 and 1.5 with the left index representing 10.

Approximate readings may be made between the graduations.

Practice enables easy positioning of the hairline. Since the graduations become closer from left to right, the 5.15 mark above is slightly to the left of the midpoint of 5.1 and 5.2.

CreditsSlide Rule ImagesDereks Virtual Slide Rule Gallery (Pickett N600-ES Log Log Speed Rule)

Slide Borders of ScalesScientific American Slide Rule Template