# The use of Metric Calipers

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The use of Metric Calipers
Acknowledgment: Thanks to Southwest Wisconsin Technical College, who provided material from which this PowerPoint presentation is derived.

Overview In this presentation you will learn about:
The different kinds of calipers. The components of a typical caliper. Taking measurements from calipers.

Introduction Calipers are used to make precise length measurements.
Several different kinds of measurements can be made with a caliper...

While both micrometers and calipers can make outside length measurements...

Calipers can also make inside measurements...

…and depth measurements.

There are three types of calipers.
The vernier caliper:

The dial caliper:

…and the digital electronic caliper.

The vernier caliper takes the most skill to read, and this is the type you will be using in experiment X.3.

These are the main features of a typical vernier caliper:
Small jaws (for inside measurements) Depth gauge Metric vernier scale Metric fixed scale Beam Jaws (for outside measurements) English vernier scale English fixed scale

Introduction and Example 1
Reading the Metric Caliper Introduction and Example 1

Reading a Caliper As you are about to see, using a vernier caliper is not difficult. You only need to make two readings: one from the fixed scale and one from the vernier portion.

Reading a caliper Start by obtaining a measurement from the fixed scale... This is the fixed scale used for the metric readings.

Reading a caliper Use the zero line on the vernier to locate your position on the fixed scale.

Reading a caliper However, since your final reading is normally in millimeters, you need view these amounts as millimeters. Each number printed on the metric scale represents centimeters. 6 cm 7 cm 8 cm 9 cm 10 cm etc.

Reading a caliper Just mentally add a 0 (zero) by each centimeter number. 60 mm 70 mm 80 mm 90 mm 100 mm

Since there are ten spaces between each numbered interval, these smallest spaces must be 1 mm each. For example, this would be 91 mm... For example, note the ten spaces in this interval. …this is 92 mm... The smallest interval on this scale is 1mm. …93 mm etc.

As you can see in this problem, we have a fixed scale measurement of 63 mm. The reading is 63 mm since the zero line has gone just beyond the 63 mm mark, but hasn’t reached the 64 mm mark.

Reading a caliper To finish we must obtain a reading from the metric vernier scale. On this scale, each line represents 0.05 mm. .05 mm .10 mm .15 mm .25 mm .20 mm etc. .30 mm .35 mm

Reading a caliper We need now to look for the point at which the fixed scale “lines up” with the vernier. This is read as .50 mm It appears that these two lines, “line up” the best.

Reading a caliper So based upon the two readings (one from the fixed scale, and one from the ruler) the length must be 63 mm mm = mm 63 mm + .50 mm 63.50 mm

Reading the Metric Caliper Example 2

Reading a caliper Let’s try another one

Reading a caliper First take a reading from the fixed scale. Use the zero line from the vernier to help. The zero line is close, but not quite up to, the 20 mm line. It has gone beyond the 19 mm line however. Remember that we need to read the fixed scale in terms of millimeters. 19 mm

To finish, read the vernier scale. This is read as .35 mm It appears that these two lines, “line up” the best. 19 mm .35 mm

The final reading then is mm. 19 mm + .35 mm 19.35 mm

Reading the Metric Caliper Example 3

Let’s go through one more example.

Use the zero line from the vernier scale to help get a reading on the fixed scale. The zero line is directly above the 8 mm line. Remember that we need to read the fixed scale in terms of millimeters. 8 mm

That’s it! Since the zero line on the vernier matched up with a line on the fixed scale, you quit right there. The final reading is 8.00 mm

Reading the Metric Caliper Practice Problem

The zero line is close to, but does not quite reach the 67 mm line. It has gone beyond the 66 mm line however. Remember that we need to read the fixed scale in terms of millimeters. 66 mm