Vernier Caliper: Understanding Measurement and Usage

Posted on Jan 8, 2025 in Mathematics

Scale in Millimeters

The degree of precision is calculated by dividing the smallest size of the major scale by the number of divisions of the vernier.

Vernier Markings

The vernier may have the following markings:

Reading Underground Foot Measurements

To see if the tube foot is graduated in the English system or the metric system, look for 10 divisions of the major scale, starting from zero.

  • If this division is not numbered, it means that the instrument belongs to the English system.
  • If compared to Division 10 there is a number, you are a graduate of the metric system.

To take a reading, you must:

  • Determine the value of each major scale division.
  • Determine the number of divisions of the vernier.
  • Calculate the degree of precision (smaller magnitude of the main scale divided by the number of divisions of the vernier).
  • Determine the position of the vernier zero on the main scale divisions. (If it matches one of the major scale, it is still read as indicating the instrument).
  • Determine which line of the vernier division coincides with any of the major scale.
  • Add the values found in the major scale, and the vernier value is the measure that indicates the instrument.

Examples

Example A (from Figure 3.18)

  • Each division of the main rule is 1 mm.
  • The vernier has 20 divisions.
  • The degree of precision is 1 / 20 = 0.05 mm.
  • The zero of the vernier passed through 30 mm on the main scale.
  • Line 7 of the vernier coincides with a scale. Reading = 7 x 0.05 = 0.35 mm.
  • Final reading: 30 + 0.35 = 30.35 mm.

Reading Underground Foot in a Fraction of Inches

Example B (Reading of Figure 3.19)

  • 1 / 16 “
  • 8 divisions of vernier
  • GP = 1 / 16 ” divided by 8 = 1 / 128″
  • Vernier zero position: 5 / 16 “
  • Line 4 of the vernier coincides with the rule. Vernier reading 1 / 32 “
  • Final reading: 5 / 16 “+ 1 / 32” = 11/32 “

Precautions When Measuring with a Caliper

  • Do not apply excessive force to the gauge.
  • Do not drop or hit it, and do not use it as a hammer.
  • Choose the gauge that best fits your needs.
  • Make absolutely sure that the type, range of measurements, graduation gauge, and other specifications are appropriate for the implementation.
  • Be careful not to damage the indoor test points.
  • Do not use the tips as a compass or grater.
  • Remove any dirt from the caliper before use.
  • Clean the sliding surfaces and the contact faces.
  • Use only paper or lint-free cloth.
  • After use, clean stains and fingerprints from the gauge with a dry cloth.
  • When the gauge is stored for long periods or needs oil, use a cloth soaked with oil to prevent rust and lightly rub each section of the gauge.
  • Make sure the oil is distributed evenly over the surface.

Storage

The following points should be considered when storing calibrators:

  • Do not expose the caliper to direct sunlight.
  • Store the gauge in a well-ventilated area of low humidity.
  • Store the gauge in a dust-free environment.
  • Do not place the gauge directly on the floor.
  • Leave the measuring faces separated by at least 0.2 mm.
  • Do not set the cursor.
  • Store the gauge in its case.