Dial and vernier calipers

The dial/vernier caliper is used to measure the inside or outside diameter of an object.
Most dial/vernier calipers have a slide, slide lockscrew, thumb button, scale, dial with measured increments of 0.001 inch, and a bezel.
For specific instructions on how to take measurements with a dial/vernier caliper, refer to either the manufacturer’s instructions or to Tools and Their Uses.
Regardless of what type of caliper you use, be sure to take the following precautions to avoid damaging the caliper:
1. Wash your hands before you handle the vernier caliper to remove dirt and oils that might damage the caliper.
2. Wipe the caliper components clean both before and after you use the caliper.
3. Do not drop or otherwise mishandle the caliper. Doing so may damage or destroy the caliper.