Metallics JBLW178 Washers No.10 Split Lock Sbrn (Jar 100)

They're No. 10 split lock washers, so they seat under a No. 10 machine screw, bolt or nut. On the job that covers most device screws, ground screws and small strut or box hardware in the No. 10 range. They come 100 to a jar.

They're silicon bronze, which is the reason to pick this one over a plain steel lock washer. Bronze holds up in wet, marine and corrosive environments and won't rust-stain the surface it sits on, so it's the usual choice for exterior boxes, grounding hardware and waterfront or pool equipment.

Pair the JBLW178 with bronze or brass hardware where you can. Silicon bronze is a dissimilar metal to plain steel and to galvanized coatings, and in a wet location that contact is where galvanic corrosion starts. Against stainless the couple is much milder. The safest build is bronze washer, bronze screw, bronze nut.

A split lock washer is cut and sprung open, so tightening the screw flattens it and the sprung ends bite into the nut and the surface. That keeps the joint from backing off under vibration. A flat washer only spreads load and does nothing about loosening. If you need both, stack a flat washer against the work surface and the split lock under the nut or screw head.

100 pieces in a jar, about 0.13 lbs total. The jar footprint is 3 in by 3 in by 2.15 in, so it fits a standard parts drawer or van bin without repackaging.