Metallics JHFW1181SS Washer 3/8 x 1-3/8 Centering Strut Wa (Jar 100)

A centering strut washer sits between the nut or bolt head and the strut channel to center the 3/8 inch fastener in the channel slot and spread the clamping load across the channel lips. The Metallics JHFW1181SS is the 3/8 x 1-3/8 size, so it takes a 3/8 inch rod or bolt and bears on a 1-3/8 inch outside diameter. Electricians use these on strut-mounted conduit racks, trapeze hangers, and equipment supports where the fastener needs to stay put while the assembly is tightened.

Yes. The JHFW1181SS is the 3/8 inch size, so it passes 3/8 inch threaded rod or a 3/8 inch bolt. In this trade 3/8 inch rod is 3/8-16 coarse thread, and a washer is sized by bore, not by thread pitch, so pitch does not change the fit. The 1-3/8 inch outside dimension is what does the work here, giving you enough bearing surface to sit across a strut slot instead of pulling through it.

One hundred washers per jar. Metallics ships the JHFW1181SS in a jar rather than a bag or a box, which is the pack contractors keep on the van for strut work because it stays closed on its side and you can pour out a handful without losing the rest into the truck bed. If you are racking conduit on a job of any size, plan on one washer per fastener point and buy jars accordingly.

A standard flat washer and a strut nut do two different jobs than this one. The strut nut grips the channel lips from inside; a plain flat washer just spreads load under the bolt head. The centering washer is what keeps the 3/8 inch fastener sitting on the centerline of the slot so the rod hangs plumb and does not drift toward one lip as you torque it. On a trapeze hanger carrying a run of conduit, that drift is what puts your rack out of line. If your assembly already locates the rod positively, a plain flat washer will do; if the rod can wander in the slot, use the centering washer.

The JHFW1181SS carries the SS suffix in the Metallics part number, which is that manufacturer's stainless designation. That is what you want for exterior conduit racks, parking structures, wash-down areas, and coastal work where a plated steel washer will bleed rust down the strut inside a season. Order it by the full number JHFW1181SS so the stainless version is what shows up, since the plated versions of the same size carry a different suffix.