Starrett 79B-4 Spring Nut Outside Spring Calliper, Steel, Flat Leg, 0-4" Range

The Starrett 79B-4 “Yankee” spring-type outside calliper opens to 4” (100 mm) with sturdy construction and smooth action. The threads of the spring nut firmly engage the screw with pressure from the leg. When pressure is withdrawn, the nut automatically releases itself and slides freely over the screw, saving time in opening and closing. It is made of flat stock, high-grade steel, for easily reproducible and accurate transfer of measurements of the external size of an object. This calliper has flat, inward curving legs for outside measurements and comes with a spring nut. Bow spring is flexible yet strong, for reliability. The durable legs are made of flat stock, high-grade steel for long life. The centrally located adjustment rod ensures smooth action when opening and closing the calliper. The hardened fulcrum stud is strong to help prevent give or play in the measurement, which would reduce accuracy.