Washers, Black Oxide Stainless Steel

Finishing a black joint, top to bottom

The washer is a small part with an outsized effect on how a finished joint looks, because it sits right under the head where any color mismatch is obvious. A bright stainless washer beneath a black oxide bolt is exactly the kind of detail that spoils an otherwise uniform black assembly, which is why black oxide washers exist: to keep the whole visible stack one color. Each style also does its normal job. A flat washer spreads clamp load and protects the surface; a split ring lock washer stores spring tension to resist vibration loosening; a cup washer cradles a countersunk head for a neat finished seat. On a stainless base the black finish is cosmetic, so the washer, often the thinnest part of the joint and the quickest to corrode if it were the wrong material, stays corrosion resistant through its metal. Match each to the fastener and the other black oxide hardware for a joint that is uniform in both finish and corrosion behavior.

Why choose black oxide stainless washers

• Matches black oxide fasteners under the head
• Stainless base keeps the thin washer corrosion resistant
• Flat washers spread load and protect the surface
• Split ring lock washers resist vibration loosening
• Cup washers finish and seat countersunk heads

Common applications

• Completing black oxide fastener joints
• Visible connections needing a uniform black look
• Anti-glare electronics and equipment
• Design-led and architectural fittings
• Countersunk screw finishing (cup washers)
• Any washer needing black looks with stainless durability

Black Oxide Stainless Washer FAQs

Why use black oxide washers?

To match black oxide fasteners under the head, keeping the visible joint uniformly black. A bright washer would stand out beneath a black bolt or nut.

Which washer type do I need?

A flat washer spreads load and protects the surface, a split ring lock washer resists vibration loosening, and a cup washer finishes a countersunk head. Choose by the job the washer has to do.

Are these corrosion resistant?

Yes, through the stainless base. Black oxide adds mild resistance; in severe salt the thin oxide may show surface rust that washes off, while the stainless protects the washer.

Does a black oxide split lock washer still lock?

Yes, the locking comes from the spring tension of the stainless washer; the black oxide is only a finish. It resists loosening as a bare stainless split washer would.

Why not black-coated steel washers?

Coated steel washers rust where the coating is thin or scratched, and washers are thin to begin with. A stainless base keeps the washer corrosion resistant, so the black stays cosmetic.

Do these match the black oxide nuts and bolts?

Yes, they are made to complete a black oxide assembly so the whole visible stack, bolt, washer, and nut, reads as one uniform black on a stainless base.