A torque wrench is calibrated using a multitest torque, force and angle testing machine at the precision measurement equipment lab on Ellsworth Air Force Base, S.D., Feb. 20, 2013. All threaded fasteners, such as bolts and nuts have torque ratings as designed by the manufacturer, and can prematurely weaken or break if they are incorrectly tightened. (U.S. Air Force photo by Airman 1st Class Anania Tekurio/Released)