Stainless Steel Cup Washers

Brass and Copper Parts India manufactures and exports a comprehensive range of Stainless Steel Cup Washers — precision deep-drawn or pressed fastener components used extensively in construction, furniture, woodworking, marine, electrical, and industrial assembly applications worldwide. Also known as screw cup washers, countersunk cup washers, dome washers, or finishing washers, our cup washers are produced from high-grade stainless steel sheet to deliver consistent cup depth, accurate bore dimensions, and a superior surface finish.

We supply standard sizes for imperial wood screws and metric countersunk screws, as well as fully custom cup washers manufactured to your drawings. For enquiries, contact us at sales@brass-copper-parts.com.

What Are Stainless Steel Cup Washers?

A cup washer is a small, dished or cup-shaped washer with a countersunk hole in the centre. When used beneath a countersunk or flat-head screw, it provides a smooth, domed, neat face on the fixing surface, distributes load, prevents pull-through in soft materials such as timber and composites, and protects the substrate from screw-head damage. Stainless steel cup washers are the preferred choice wherever corrosion resistance, durability, and aesthetics are important — including marine deck fittings, outdoor furniture, electrical enclosures, signage, architectural glazing fixings, and wood construction.

Types of Stainless Steel Cup Washers We Manufacture

• Standard Cup Washers – For imperial No.4 to No.14 wood screws (most common range)
• Metric Cup Washers – For M3, M4, M5, M6, M8, M10 countersunk screws
• Large-Diameter Cup Washers – For panel fixings and industrial applications
• Mirror-Polished Cup Washers – For visible architectural and decorative fixings
• Flanged Cup Washers – Larger bearing surface for soft substrates
• Thick-Section Cup Washers – For heavy-duty structural applications
• Custom Cup Washers – Manufactured to customer drawing and specification

Material Grades & International Equivalents

Surface Finishes Available

Dimensional Range

Why Choose Brass and Copper Parts India for Stainless Steel Cup Washers?

• Precision Deep-Drawing Capability – Consistent cup depth, burr-free edges, and accurate bore in every piece
• Full Range of SS Grades – SS 304, 304L, 316, 316L, 430, 201 in stock and available to order
• Custom Sizes and Profiles – Manufactured to drawing for non-standard requirements
• High-Volume Manufacturing Capacity – Suitable for OEM and bulk supply contracts
• Competitive Factory-Direct Pricing with no intermediary markups
• Strict Quality Control – 100% dimensional check, surface finish inspection, hardness testing
• Fast Dispatch – Standard sizes typically shipped within 7–10 business days
• Export Packaging – Secure, moisture-protected packaging for international shipments
• Global Customer Base – Trusted by furniture manufacturers, marine engineers, and construction firms worldwide

Frequently Asked Questions – Stainless Steel Cup Washers

Q1. What is a stainless steel cup washer used for?

A stainless steel cup washer is placed beneath the head of a countersunk screw to provide a neat, decorative finish, distribute load over a larger surface area, and prevent the screw head from pulling through or damaging soft materials like timber, composites, or thin sheet. They are widely used in furniture manufacturing, marine decking, outdoor structures, electrical enclosures, architectural signage, and woodworking.

Q2. What is the difference between SS 304 and SS 316 cup washers?

SS 304 (A2) is the most common grade, offering excellent general-purpose corrosion resistance suitable for most indoor and outdoor environments. SS 316 (A4) contains molybdenum which provides superior resistance to chloride corrosion, making it the preferred choice for marine, coastal, and chemically aggressive environments. For seawater or salt-spray exposure, SS 316 is strongly recommended.

Q3. What screw sizes are your cup washers designed for?

We manufacture cup washers for imperial wood screw sizes No.4 through No.14, and metric countersunk screw sizes M3 through M10. The countersink angle is 82° for imperial screws and 90° for metric (DIN 7991 standard). Custom sizes and angles are also available.

Q4. Can you supply mirror-polished stainless steel cup washers?

Yes. We supply No. 8 mirror-polished cup washers in both SS 304 and SS 316 grades for decorative and architectural applications where visible fixings need to match a high-gloss finish. These are particularly popular for glass balustrade fixings, marine interiors, and premium furniture.

Q5. Are your stainless steel cup washers magnetic?

SS 304 and SS 316 are austenitic grades and are generally non-magnetic in the annealed state, though they may exhibit slight magnetism after deep-drawing due to work hardening. SS 430 is ferritic and fully magnetic. If your application requires non-magnetic cup washers, specify SS 304 or SS 316 and we will minimise work hardening in our pressing process.

Q6. What is the minimum order quantity for stainless steel cup washers?

Standard MOQ is 1,000 pieces for catalogue sizes. Custom or special-finish cup washers may have different MOQs. We are happy to discuss trial orders for new customers — contact us at sales@brass-copper-parts.com.

Q7. Do you supply cup washers to DIN or ISO standards?

Yes. We manufacture cup washers to DIN 967, BS 4320, and customer-specified standards. For metric screws the standard countersink is 90° per DIN 7991. We can also produce to ANSI, JIS, and other international standards on request.

Q8. Can you manufacture oversized or custom cup washers?

Yes. Custom cup washers with non-standard outer diameters, depths, bore sizes, or flange profiles are a regular part of our production. We work from customer drawings, CAD files, or samples. Tooling is manufactured in-house for quick turnaround on new custom profiles.

Q9. How do stainless steel cup washers compare to brass or copper cup washers?

Stainless steel cup washers offer superior corrosion and mechanical strength compared to brass or copper. Brass cup washers provide an attractive gold finish and are preferred for timber joinery and heritage applications. Copper cup washers offer excellent conductivity and are used in electrical and grounding applications. We manufacture all three materials — contact us to specify your requirement.

Q10. Are your stainless steel cup washers RoHS compliant?

Yes. All stainless steel grades we use comply with RoHS and REACH regulations. Material test certificates confirming chemical composition and mechanical properties are available on request for every batch.

Q11. What surface finish do your standard cup washers have?

Our standard cup washers come in a 2B mill finish, which is smooth, slightly reflective, and suitable for most general industrial, construction, and furniture applications. No. 4 brushed, mirror polished, passivated, and electropolished finishes are available as upgrades.

Q12. What is the lead time for stainless steel cup washers?

Standard catalogue sizes are typically dispatched within 7–10 working days. Custom sizes requiring new tooling have a lead time of 3–4 weeks from drawing approval. We can accommodate rush orders for urgent requirements — please contact us to discuss availability.

Q13. Can you supply cup washers for the marine and offshore industry?

Absolutely. SS 316L is our most popular grade for marine and offshore applications due to its superior resistance to chloride and salt-spray corrosion. We can also supply passivated or electropolished cup washers for maximum corrosion protection in seawater environments.

Q14. Do you provide material test certificates with cup washers?

Yes. Mill material test certificates (MTCs) confirming grade, chemical composition, and mechanical properties are provided with every order. Third-party inspection is also available through SGS, Bureau Veritas, or any agency specified by the customer.

Customer Reviews

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“We source SS 316 cup washers from Brass and Copper Parts India for our marine deck furniture range. The finish quality is consistently excellent, parts are well-packed, and delivery to our facility is always on schedule. Their pricing is very competitive for high-grade stainless steel components. We are very satisfied customers.”
— Operations Director, Marine Furniture Manufacturer | New Zealand

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“We required mirror-polished SS 304 cup washers for our premium office furniture collection. Brass and Copper Parts India provided samples quickly, and when we confirmed the order, production and delivery were smooth and timely. The mirror finish matched our specification perfectly. We now use them as our preferred supplier for all pressed stainless components.”
— Product Development Manager, Premium Furniture Manufacturer | Germany

📧 Contact us: sales@brass-copper-parts.com | Brass and Copper Parts India