Forging new generations of engineers

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## Forging new generations of engineers

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**The English Scale**The English scale is an instrument that is used to measure linear distances. A typical English scale is made up of 12 inches.**Scale Accuracy**The inch is fractioned into smaller increments. Usually, the smallest increment is 1/16th of an inch. How big is 1/16th on an inch? You would need to stack about 16 sheets of paper to equal 1/16th of an inch.**Common Items: Size Comparison**Paper Clip dia. Two sheets of Paper stacked Human hair dia. 1/32 inch .031 1/256 inch .003 1/128 inch .008 Proportioned section diagrams**The INCH**The divisions on an English scale are easily identified by different sized markings. The largest markings on the scale identify the inch.**The INCH**All subsequent sized markings can be found by taking half of the previous measurement. i.e., half of an inch = ½ inch 1/2**The INCH**Half of a half = ¼ inch. An English scale shows ¼ inch and ¾ inch marks. All fractions must be reduced to lowest terms. 3/4 1/4**The INCH**Half of a quarter = 1/8 inch 1/8 3/8 5/8 7/8**The INCH**Half of an eighth = 1/16 inch 1/16 5/16 9/16 13/16 3/16 7/16 11/16 15/16**Now Let’s practice**Question 1: What is the distance of A?**What would be the metric answer?**The Fractional answer is: .25 x 25.4= 6.35 or 6mm if rounding to the nearest mm. 6mm ¼”**The Metric Scale**The metric scale is another instrument that is used to measure linear distances. A typical metric scale is made up of approximately 300 mm.**Scale Accuracy**The metric scale is divided into very small increments called millimeters (mm). There are 25.4 mm in one inch.**The Millimeter**The millimeter is the smallest increment found on a typical metric scale. 1 mm**The Millimeter**The next larger marking on a metric scale shows 5 millimeters. 5 mm**The Millimeter**The largest markings on the metric scale represent centimeters (cm). These are the only marks that are actually numbered. 1 cm = 10 mm**Let’s Practice**What would the answer be if converted to inches? What is the metric answer for B 19mm ¾”