Reading and Setting a Measurement on a Decimal-inch Vernier Caliper
A measurement is read by adding the thousandths reading on the vernier scale to the reading from the main scale.
Procedure
�?To read a measurement on a decimal-inche vernier caliper
�?Read the number of 1 �?graduations, 0.1�?graduations, and 0.025″graduations on the main scale that are left of the zero graduation on the vernier scale.
�?On the vernier scale, find the graduation that most closely coincides with a graduation on the main scale. Add this vernier reading, which indicates the number of 0.001″graduations to the main scale reading.
Setting a given measurement is the reverse procedure of reading a measurement on the vernier caliper.
Example 1 Read the measurement set on this vernier caliper.In reference to the zero division on the vernier scale read two 1″divisions.0.1″divisions, and three 0.025�?divisions, and three 0.025″divisions on the main scale.
(2�?0.7�?0.075�?2.775�?
Observe which vernier scale graduation most closely coincides with a main scale graduation. The 8 vernier scale graduation concides; therefore, 0.008″is added to 2.775�?
Measuremtent: 2.775�? 0.008�? 2.783�?br />
Example 2 Set 1.237″on a vernier caliper
Move the vernier zero graduation to 1�? 0.2�?0.025″on the main scale.
An additional 0.012�?1.237 �?1.225�? is set by adjusting the sliding jaw until the 12 graduation on the vernier scale coincides with a graduation on the main scale.
The accuracy of measurement obtainable with a vernier caliper depends on the user’s ability to align the caliper with the part that is being measured and the user’s “feel”when measuring. The line of measurement must be parallel to the beam of the caliper and lie in the same plane as the caliper. Care must be used to prevent a caliper setting that is too loose or too tight.
The front side of the customary vernier caliper (25 divisions) is used for outside measurements. The reverse or back side is used for inside measurements.