Precision locknuts are used to adjust, preload, and secure bearings, gears, and other power transmission products to shafts and spindles with a high degree of stiffness. They have machined internal threads and sturdy faces that provide strong metal-to-metal locking without distortion. Precision locknuts are sometimes referred to as bearing locknuts since the dimensions of these locknuts are made to correspond with standard bearing sizes. Most precision locknuts are tightened with a spanner wrench. Right-handed threads are tightened with clockwise turns. Left-handed threads are tightened with counterclockwise turns. Typically, setscrews on the face or periphery of the locknut are used to lock the female threads of the locknut to the male threads of the shaft.