Copyright Goodheart-Willcox Co., Inc. 102 Section 1 Introduction to Plumbing 6.1 Measurement The basic measuring tools used by the plumber are the folding rule and the steel tape. Whichever is used, the scale printed on the tool is the same. Figure 6-1 illus- trates how the basic scale is divided into parts of an inch. 6.1.1 Reading Fractions of an Inch Reading a rule accurately and quickly requires care- ful attention to the markings on the scale and some practice. The lines marking the scale vary in length. The longest lines are the inch divisions. The short- est lines on many rules are sixteenths of an inch. Figure 6-2 shows several examples. The easiest way to read a scale accurately to the nearest 1/16″ is to use the 1/4″ divisions as a start- ing point. Then add or subtract the smaller parts of an inch from the larger divisions to get the correct reading, Figure 6-3. This method is much faster and 1 2 2 1 1 2 1 2 2 1 1 2 1 4 3 4 1 4 3 4 1 2 2 1 1 2 1 4 3 8 1 8 3 4 7 8 5 8 1 4 3 8 1 8 3 4 7 8 5 8 1 2 2 1 1 2 1 4 3 8 1 8 1 16 3 16 5 16 7 16 9 16 11 16 13 16 15 16 1 16 3 16 5 16 7 16 9 16 11 16 13 16 15 16 3 4 7 8 5 8 1 4 3 8 1 8 3 4 7 8 5 8 1 2 Inch dimensions ½″ dimensions divide each inch into two equal spaces ¼″ dimensions divide each inch into four equal spaces 1⁄8″ dimensions divide each inch into eight equal spaces 1⁄16″ dimensions divide each inch into sixteen equal spaces Goodheart-Willcox Publisher Figure 6-1. Reading a standard rule accurately and quickly is a skill that every plumber must master. Study the fraction above to fix the division of an inch firmly in your mind. 1 2 3 4 5 6 1 2 3 1 2 3 4 5 1 2 3 4 51⁄8″ 41⁄2″ 33⁄16″ 23⁄4″ Goodheart-Willcox Publisher Figure 6-2. Learn to recognize each scale marking by length and position.