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Lesson 5: Narration Script | ||||||||
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The distance from the zero line to the first large numbered line, or graduation, is a distance of one hundred thousandths of an inch. | ||||||||
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Likewise, the distances from the second numbered line to the third line is also one hundred thousandths. Each of these large lines, or graduations, is read in hundreds of thousandths. | ||||||||
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Between each of the large numbered spaces are four smaller spaces. | ||||||||
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Each space measures twenty five thousandths as you move from the zero to the right. | ||||||||
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The first small space measures twenty five thousandths. The second space totals fifty thousandths. | ||||||||
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The third space marks a distances of seventy five thousandths, and at the end of the fourth space is the large graduation representing one hundred thousandths. | ||||||||
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The lines on the thimble divide the thimble in to twenty five spaces. Each space represents one thousandth of an inch. | ||||||||
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If the baseline is between spaces on the thimble, only the last full space is counted. In this example do not count this space. | ||||||||
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Therefore, this scale is displaying a value of twenty-four thousandths. | ||||||||
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All measurements of a work piece must be compared to a standard size. You will find the standard size requirements on either a shop print as shown here, or on a job lay-out sheet. | ||||||||
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When working with metric dimensions, you must use a metric micrometer to make measurements. A metric micrometer works the same way as an inch micrometer. The difference is the unit of measure represented on the sleeve and thimble scales. | ||||||||
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The graduations on the sleeve below the baseline represent whole millimeters. | ||||||||
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Page 5
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