Wedge lock washers have earned their reputation. Two cammed washers, ramp angles steeper than the bolt's thread pitch, and any rotation under vibration increases clamp load instead of releasing it. On paper and in Junker vibration testing, they're one of the best anti-loosening devices you can put on a joint. But “best at preventing loosening” and “prevents a drop” are different claims — and on overhead hardware the difference is the whole game.
What wedge lock washers do well
- Vibration resistance — the cam geometry defeats the transverse vibration that walks ordinary fasteners loose.
- Reusability and simple installation — no chemicals, no cure time, no drilled heads, standard torque procedure.
- Temperature and lubrication tolerance — they work where thread lockers age out and nylon-insert nuts derate.
If your maintenance findings are full of backed-off guard bolts, upgrading those joints to wedge lock washers is a legitimate engineering improvement.
What they can't do
A wedge lock washer only works while the system is intact and correctly installed. Real-world joints fail in ways the catalog page doesn't show: washers installed as two separate pieces or facing the wrong way, joint relaxation and gasket creep bleeding off preload, fatigue cracking the fastener itself, corrosion, or the wrong washer pairing for the flange. When any of that happens, the washer has no second act. The bolt is loose in its hole, and the only thing between it and the floor is time.
Loosening prevention vs. drop prevention
Every locking method — wedge washers, thread lockers, prevailing-torque nuts, safety wire — answers the question “how do I keep this joint tight?” Overhead hardware demands a second question: “what happens if it comes loose anyway?” For a bolt over a walkway, workstation, or traffic lane, the acceptable answer is never “it falls.” That's the job of secondary retention: an engineered tether that keeps the fastener attached to the structure even fully backed out — hanging, visible, and recoverable.
Use both, by location
This isn't either/or. Keep wedge lock washers (or your preferred locking method) for joint integrity everywhere it makes sense. Then rank your fastener locations by height and by what sits underneath during a shift, and add tethered retention to the ones where a drop reaches people or critical equipment. The washer protects the joint; the tether protects the crew.
CraneBolts tethered safety bolts pair standard installation with patent-pending captive retention — made to order in the USA. Request a quote.