How to Read Millimeters on a Dial Caliper

A dial caliper has both a scale and a dial.

Calipers are used to measure the distance from one side of an object to another. There are various types of calipers --- some measure holes inside of objects, some measure the outside of an object and some hold a pen to draw precise lines. The dial caliper's advantage over other caliper types is that it is much easier to read, especially with those who are not experienced in reading these types of tools. It uses a combination of a scale and a dial to display the millimeter reading.

Instructions

1. Insert the dial caliper into the space to be measured. Move the index until it fits snugly into the space.

2. Find the closest large number visible on the scale to the left of the index. Write this number down, and write a decimal point after it.

3. Find the closest small number visible on the scale to the left of the index. Write this number after the decimal point.

4. Find the number that the dial is pointing to, and multiply that number by .001.

5. Add the number in Step 4 to the number in Step 3.

Tips & Warnings

• For areas larger than your dial caliper can measure, you can purchase an extending base to go with the caliper.

• Do not use too much force when adjusting the caliper. Use a firm touch, but do not press the caliper against the edges.

• Keep the calipers from getting dirty. Dirt can get lodged in the gears, leading to inaccurate readings.

References

• WISC Online: How to Read a Caliper