top bar
Chapter 1. Basic Machining and Tips


How to Use Vernier Callipers

In the machining process, we use vernier callipers or a micrometer for taking measurements. General analog vernier callipers as shown in Figure 1 can measure with the minimum unit of 1/20 mm. Several types of digital vernier callipers as shown in Figure 2 can measure with the minimum unit of 1/100 mm.

Fig. 1, Analog Vernier Callipers

Fig. 2, Digital Vernier Callipers


The vernier callipers can measure a side length, an outer and inner diameter, and a depth as shown in Figures 3 to 6.

Fig. 3, Measurement of an Outer Diameter

Fig. 4, Measurement of a Side Length

Fig. 5, Measurement of an Inner Diameter

Fig. 6, Measurement of a Depth

Keep a perpendicular position in measuring!

The vernier callipers must be kept the perpendicular position in measuring. Typically, when a beginner measures the size of a complex shaped part, the result can be inaccurate as the measuring device is often not maintained parallel to measured piece.

How to Use a Micrometer

When close tolerances are required, measurements are taken with a micrometer due to its superior accuracy over a vernier calliper. The micrometer as shown in Figure 7 can measure with the minimum unit of 1/1000 mm.

Fig. 7, Micrometer

Fig. 8, Measurement with a Micrometer

Which do you use the vernier callipers or the micrometer?

The "For & Against" of using micrometers and vernier callipers are:

Vernier Calliper:
For: A large range of measurements can be made using the one measuring device.
Against: The majority of vernier callipers do not provide sufficient accuracy for close tolerance measurements.

For: The micrometer provides a greater degree of accuracy for close tolerance work.
Against: Due to the limited size range for a given micrometer, it is necessary to have a number of micrometers to cater for the full range of measurements you may encounter.

[ Metal Working TOP ] [ Hirata HOME ] [ Power and Energy Engineering Division ] [ NMRI HOME ]
bottom bar