How Do You Measure Caliper Size?

To measure with calipers, you read the main scale for the full millimeters up to the zero mark of the vernier scale.

Here's a breakdown of how to read calipers accurately:

1. Locate the Main Scale: This is typically the fixed scale on the caliper.
2. Identify the Zero Mark on the Vernier Scale (or sliding scale): This is the key reference point for your initial measurement.
3. Read the Full Millimeters: On the main scale, find the last millimeter marking before the zero mark on the vernier scale. This gives you the whole millimeter value. For example, if the zero mark is past the 22mm mark on the main scale, you have at least 22mm.
4. Estimate the Fraction (if using an analog caliper): Determine which line on the vernier scale best aligns with a line on the main scale. The value of this line on the vernier scale represents the fraction of a millimeter. Add this fraction to your whole millimeter reading. Digital calipers will directly display the fractional part.

For example, in the reference video, the full millimeter reading is 22mm. You would then look at the vernier scale (if it's an analog caliper) to determine the fractional millimeter.