As a screw is tightened, these metric washers flatten to add tension to the joint, counteracting fatigue around the joint from small amounts of vibration. This makes them a common choice to prevent fasteners from loosening. However, they resist the least amount of vibration compared to other locking washers. They meet a DIN or ASME standard for split lock washer dimensions.

Standard split lock washers have a left-hand helix that have right-hand threads to prevent loosening. They have uneven split ends that bite into fasteners for a tight grip but won’t work with hardened surfaces. They hold better than curved or wave washers. These washers are not reusable after tightening.

Steel washers are stronger and resist wear better than zinc-plated steel and stainless steel washers. Use them in dry environments. Blue-dyed steel washers are easy to spot.

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