Stainless Steel Washers
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What are stainless steel washers? Stainless steel washers are corrosion-resistant plates with a center hole placed under a bolt head or nut to spread load, protect the surface, space parts, or resist loosening. Made from 18-8, 304, and 316 stainless, plus A2 and A4 metric grades, they hold up in wet, coastal, and outdoor use where plated washers rust.
Washers, Stainless Steel
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Stainless Steel Flat washers
Corrosion-resistant round flat washers in 18-8, 304, 316, and metric A2/A4 stainless that spread load and protect the surface.
Stainless Steel Fender Washers
Corrosion-resistant oversized flat washers in 18-8, 304, 316, and metric A2/A4 stainless that spread load across thin or soft material.
Stainless Steel Lock Washers
Corrosion-resistant lock washers in 316 and metric A2/A4 stainless that resist loosening from vibration with spring tension or biting teeth.
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Stainless Steel Cup Washers
Corrosion-resistant recessed finishing washers in 18-8, 316, and A4 stainless that cradle a countersunk screw head for a clean look.
Stainless Steel Square Washers
Corrosion-resistant four-sided washers in 304 and 316 stainless with a large bearing area for wood, timber, and structural connections.
Stainless Steel Sealing Washers
Bonded or standalone neoprene/EPDM washers that seal fastener holes against water on roofing, siding, and outdoor panels.
Stainless Steel Conical Washers
Cone-shaped spring washers that flex under load to maintain tension and resist loosening in high-vibration or thermal-cycling joints, also known as belleville washers.
Matching washer grade to your fastener
A stainless joint is only as corrosion resistant as its weakest part, so pair the washer grade to the bolt and nut. Use 18-8 or 304 for indoor and general outdoor work, and 316 for coastal and saltwater exposure. For metric assemblies, A2 stainless is comparable to 304 and A4 to 316. Choosing the same grade across bolt, nut, and washer avoids a rust point and reduces galvanic corrosion between dissimilar metals.
Types of stainless washers
- Flat washers: spread load and protect the surface.
- Fender washers: oversized outer diameter for thin or soft material.
- Lock washers: resist loosening from vibration.
- Square, cup, and specialty washers: for wood, finish, and specific jobs.
Common applications for stainless washers
- Spreading load under bolts and nuts
- Marine, dock, and coastal hardware (use 316 or A4)
- Decks, fences, and outdoor structures
- Food-grade and wash-down equipment
Pair these with matching stainless nuts and bolts, and browse every washer type and finish on the main washers category.
Stainless Steel Washers FAQ
What stainless grades do your washers come in?
Inch washers come in 18-8, 304, and 316, and metric washers in A2 and A4. A2 is comparable to 304 and A4 to 316.
Should my washer match my bolt grade?
Yes. Pairing the same grade across bolt, nut, and washer avoids a corrosion weak point and reduces galvanic issues in wet environments.
Which washer grade for coastal use?
Use 316 or metric A4 for coastal, saltwater, and chloride exposure, since they resist pitting better than 18-8, 304, or A2.