Metallics JSSW16 Washers 4 Flat Large OD SS (Jar 100)

The JSSW16 is a #4 flat washer, so it is sized for #4 machine screws and small sheet metal screws. It is the large outside diameter version, which spreads the bearing load over more material than a standard #4 washer, useful on thin sheet metal, plastic enclosures, or oversized or slotted holes in a device box or panel.

Solid stainless steel, not plated steel. That matters for outdoor fixtures, wet locations, coastal work, and wash-down areas where a zinc-plated washer will bleed rust onto a finished surface. For dry interior panel work a plated washer is adequate, but anything exposed to moisture is where this one earns its place.

100 pieces, packed in a jar rather than a bag, so the count stays contained on a cart or in a van drawer. The whole jar weighs 0.09 lbs, which tells you how small a #4 washer is, worth knowing if you are stocking a truck or a shop bin for repetitive device and fixture work.

Pick the large OD when the hole is oversized, slotted, or in thin or soft material and the screw head would otherwise pull through. A standard #4 flat washer is the right call when the clearance hole is tight and the washer has to sit inside a small counterbore or a recessed boss, since the bigger outside diameter can foul the surrounding feature. The JSSW16 is the large OD #4 version.

No. A flat washer spreads load and protects the surface, nothing more. If the assembly vibrates you need a lock washer, a serrated flange, or a thread locker; the JSSW16 is a plain flat washer and will not resist back-off on its own. Many installers stack a flat washer under a lock washer so the lock washer teeth do not chew into the finish.

You can, but watch the dissimilar metal contact. Stainless against aluminum in a damp or coastal location sets up galvanic corrosion at the aluminum, so keep the pairing to dry interior locations or isolate it. Stainless washer on a stainless or plated steel screw is the straightforward combination. The JSSW16 is a stainless #4 flat washer.

Country of origin is listed as multiple, meaning Metallics sources the JSSW16 from more than one manufacturing country. If you are bidding work with a domestic sourcing requirement, that is the detail to flag before you spec this jar.