Metallics JWW87 Washers 1 USS Flat St-zn (Jar 25)

The JWW87 is sized for 1 inch bolts. It's a USS pattern flat wrought washer, so it carries the wider outside diameter and larger clearance hole of the USS series rather than the tighter SAE pattern. If you're bolting through sheet metal, strut, or wood where you need to spread the load, USS is the one you want; for a close fit against a machined surface or inside a counterbore, an SAE 1 inch washer is the better choice.

25 washers per jar. The pack is a screw-top jar rather than a loose box, which is why it works on a service truck or a parts shelf without spilling. Total shipping weight is 4.217 lbs for the jar.

That's exactly the intended use. Metallics lists the JWW87 for the electrical, plumbing, heating and air conditioning trades, and a 1 inch USS flat washer is the common pairing under a nut on threaded rod, strut channel, or a trapeze hanger where the bearing load needs spreading. It is a plain flat washer, so it gives you load distribution only, not locking: add a lock washer or a nylon-insert nut where vibration is a factor.

Heavy duty is how Metallics describes it, and the wrought USS construction backs that up: a wrought flat washer is a solid stamped and formed steel part rather than a thin light-pattern punching, which is what lets it sit under a 1 inch nut without cupping. For MRO stocking, this is the washer you standardize on for anchor bolts, equipment mounts, and rod hangers at 1 inch diameter.