Caliper, << KAL uh puhr, >> is an instrument used to take small measurements. A caliper has two legs joined by a rivet or screw that allows them to open and close. Outside calipers measure the outside of pipes, boards, and other objects. The open ends are fitted against the object. The legs curve inward so they can circle round objects. Inside calipers measure the inside of pipes and other open objects. The legs curve outward. A double caliper combines the inside and outside calipers. Spring calipers have a spring to automatically open their legs. A micrometer caliper is a type of slide caliper that has a fine, threaded micrometer screw and can measure to 1/10,000 inch (0.00254 millimeter). Some calipers show measurements on a built-in electronic screen. See also Micrometer ; Vernier .
