Hold threaded fasteners in place. Lock washers have special features, such as teeth, that grip the material to prevent rotation.
The most common lock washer type, split washers have offset ends that bite into fastener heads and fastened materials to lock in fasteners if they start to loosen.
Maximize locking power with wedge washers. These two-part ridged washers grip each other, the fastener, and the fastened material to hold everything in place.
Inner-diameter teeth grip the underside of fastener heads and dig into the fastened material to help prevent movement in low-torque applications.
Choose internal over external tooth washers for small-head fasteners, to resist snags, or to provide a more polished appearance.
Teeth along the outer diameter dig into the underside of screw heads and the fastened material to prevent movement in low-torque applications.
Choose external over internal tooth lock washers when your screw or bolt head is nearly as wide as the washer's OD.
Keep countersunk screws in place. Angled external teeth on these washers grip flat- and oval-head screws to prevent movement.