Metallics JSLW34 Washers 3/4 Split Lock SS (Jar 100)

The JSLW34 is a 3/4 inch split lock washer, so it goes under the nut on 3/4-10 or 3/4-16 bolts and threaded rod. Sizing on lock washers is by the nominal bolt diameter, not the washer OD, so pair it with 3/4 inch hardware only. A 5/8 or 7/8 bolt needs its own size.

Stainless steel is the material, which is why electrical crews reach for them on rooftop strut runs, exterior unistrut, wet locations and anywhere a plated washer would rust and seize the nut. Keep the bolt, nut and washer all stainless to avoid mixing dissimilar metals in the joint.

One hundred 3/4 inch stainless split lock washers per jar, packed in a jar rather than a bag or box, which is the format that survives a gang box or a service van drawer. The jar ships at 3.93 lbs and measures 3.5 x 3.5 x 5.75 inches.

They do different jobs. A split lock washer like the JSLW34 bites into the nut face and the joint surface to resist vibration loosening; a flat washer spreads load over soft or oversized material and does nothing about vibration. On equipment mounts, transformer pads, motor bases and strut where vibration is present, many installers use both: flat washer against the material, split lock washer under the nut.

Mechanically yes, the 3/4 size mates with any 3/4 bolt. Electrically, mixing stainless against galvanized in a wet or exterior location sets up galvanic corrosion at the washer, and the zinc coating gives up first. Indoors and dry it is a non-issue. For outdoor galvanized runs, match the washer to the rest of the hardware.

It's built to the ANSI dimensional standard for split lock washers, so the inside diameter, width and thickness match what a 3/4 inch regular-series lock washer should be. That matters if you are standardizing a facility's fastener stock, since replacements from another ANSI-dimensioned 3/4 lock washer will interchange.

Stainless split lock washers are commonly used on 3/4 hardware for ground bar and bonding-jumper bolting where vibration could back a nut off. Note they are not a listed grounding device themselves, they are a fastener component, so whatever bonding method your inspector is signing off on still needs to be the listed lug or connector.