01b vernier caliper

Vernier Calipers

Chapter 5- Measurement

Introduction

Vernier calipers are tools used in home, small shop, and industrial settings.

They are used to make precise length measurements.

Introduction

Some reasons for their popularity include:

Wide measuring range (usually 0 - 6”). English and metric scales are usually

found on the same instrument. Many different kinds of measurements

can be made with a caliper...

Introduction

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

Introduction

Calipers can also make inside measurements...

Introduction

…and also depth measurements.

Introduction

There are three types of calipers. The vernier caliper:

Introduction

The dial caliper:

Introduction

…and the digital electronic caliper.

Introduction

In this lesson, we will concentrate on the vernier caliper since it takes the most skill to read.

Introduction

These are the main features of a typical vernier caliper:

Jaws (for outside measurements)

Small jaws (for inside measurements)Metric vernier scaleMetric fixed scale

English vernier scaleEnglish fixed scale

Beam

Depth gauge

Introductionand

Example 1

Reading a Caliper: metric

As you are about to see, working with the metric portion of a vernier caliper is a bit easier to deal with.

You only need to make two readings: one from the fixed scale and one from the vernier portion.

Reading a caliper: metric

Start by obtaining a measurement from the fixed scale...

This is the fixed scale used for the metric readings.

Reading a caliper: metric

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

Reading a caliper: metric

Each number printed on the metric scale represents centimeters.

6 cm

However, since your final reading is supposed to be in millimeters, you need view these amounts as millimeters.

7 cm 8 cm 9 cm 10 cmetc.

Reading a caliper: metricOne “trick” is to mentally add a 0 (zero) behind each centimeter number.

0

60 mm

0 0 0 0

70 mm 80 mm90 mm 100 mm

Reading a caliper: metricSince there are ten spaces between each numbered interval, these smallest spaces must be 1 mm each.

For example, note the ten spaces in this interval.The smallest interval on this

scale is 1mm.

For example, this would be 91 mm...…this is 92 mm...…93 mm etc.

Reading a caliper: metricAs 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: metricTo 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.20 mm.25 mm.30 mm.35 mmetc.

Reading a caliper: metricJust as we did on the English vernier scale, we need to look for a place where a line from the fixed scale “lines up” with a line on the vernier.It appears that these two

lines, “line up” the best.

This is read as .50 mm

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

63 mm.50 mm+

63.50 mm

Example 2

Reading a caliper: metric

Let’s try another one for practice.

Reading a caliper: metric

First take a reading from the fixed scale. Use the zero line from the vernier to help.

Remember that we need to read the fixed scale in terms of millimeters.

The zero line is close, but not quite up to the 20 mm line. It has gone beyond the 19 mm line however.

19 mm

0 0 0

19 mm

Reading a caliper: metric

To finish, read the vernier scale.It appears that these two lines, “line up” the best.

This is read as .35 mm

.35 mm

19 mm

Reading a caliper: metric

The final reading then is 19.35 mm.

.35 mm+19.35 mm

Reading a caliper: metric

Let’s go through one more example.

Quiz # 01

• Write in mm.1. Least count2. Fixed scale reading3. Vernier scale reading4. Total reading

• Write at least 4 fire safety precautions for workshops