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Home > Tools & Hardware > Hardware Accessories > Spring > Double Coil Spring Washer With Mill Test Report and 12-Month Warranty

Double Coil Spring Washer With Mill Test Report and 12-Month Warranty

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Product Spotlights

Double coil design for superior anti-loosening performance; Mill Test Report included for full material traceability; 12-month warranty ensures peace of mind; custom sizes and surface treatments available; over 25 years of manufacturing experience with global export reach.

Negotiable MOQ: 1 Piece (Price negotiable depending on order volume and customization)

Key Specifications

Get Latest Price

Material:

Other, Carbon Steel, Stainless Steel, Alloy Steel

Size Range:

M3 - M30 (Customizable)

Surface Treatment:

Plain, Zinc Plated, Phosphate, Dacromet

Contact Supplier Request Quote Chat Now

Anping County Boli Hardware Wiremesh Products Factory

2Yrs

Payment & Shipping

Payment Methods:

Port of Shipment:

tianjin shanghai qingdao

Delivery Detail:

Delivery time depends on order quantity.

Product Details
Company Profile
Contact Us

Material Other, Carbon Steel, Stainless Steel, Alloy Steel

Size Range M3 - M30 (Customizable)

Surface Treatment Plain, Zinc Plated, Phosphate, Dacromet

Standard DIN 127, DIN 7980, ASME B18.21.1

Packing Carton, Pallet, or as per customer requirement

Warranty 12 Months

Mill Test Report Available upon request

Application Automotive, Construction, Machinery, Aerospace

Welcome to Anping County Boli Hardware Wiremesh Products Factory – a trusted manufacturer established in 1998, specializing in precision fasteners and hardware products. Our Double Coil Spring Washer with Mill Test Report and 12-Month Warranty is engineered to deliver superior locking performance and long-term reliability. Each washer is backed by a comprehensive Mill Test Report (MTR) ensuring material traceability and mechanical integrity, and our 12-month warranty gives you added confidence in your supply chain. Whether you are securing heavy machinery, automotive assemblies, or structural components, our double coil design provides consistent elastic force to prevent loosening under vibration and dynamic loads.

Manufactured from high-grade carbon steel, stainless steel, or alloy steel, these washers undergo strict quality control at every stage – from raw material inspection to final packaging. The unique double coil structure offers increased spring deflection and higher load capacity compared to standard single coil washers, making them ideal for applications where safety and durability are critical. Our factory is equipped with modern production lines and experienced technicians, capable of handling both standard sizes (M3 to M30) and custom dimensions according to your drawings or samples.

Key Features and Benefits:

Double Coil Design – Provides higher spring force and better resistance to vibration loosening, reducing the need for retightening and maintenance.
Mill Test Report Included – Each batch comes with a chemical composition and mechanical property report, ensuring full material traceability and compliance with international standards.
12-Month Warranty – We stand behind our product quality. If any defect occurs under normal use within one year, we offer free replacement or refund.
Wide Material Selection – Carbon steel (C67, 65Mn), stainless steel (304, 316), and alloy steel (SCM435) available to suit different environments, including corrosive or high-temperature conditions.
Customizable Surface Treatments – Options include plain, zinc plated, phosphate, Dacromet, or black oxide to enhance corrosion resistance and appearance.
Compliance with International Standards – Our washers meet DIN 127, DIN 7980, ASME B18.21.1, and other common specifications, ensuring interchangeability and global acceptance.
Strict Quality Control – In-house testing for hardness, dimensional accuracy, and spring deflection ensures consistent performance.

Technical Specifications (Typical Values):

Size (M)	Inner Diameter (mm)	Outer Diameter (mm)	Thickness (mm)	Free Height (mm)
M6	6.4	12.0	1.5	3.0
M8	8.4	16.0	2.0	4.0
M10	10.5	20.0	2.5	5.0
M12	13.0	24.0	3.0	6.0
M16	17.0	30.0	3.5	7.0

Note: Custom sizes and non-standard dimensions are available upon request. Contact our sales team for specific requirements.

Why Choose Our Double Coil Spring Washer?

Enhanced Safety – The double coil design ensures that even under extreme vibration, fasteners remain tight, preventing catastrophic failures.
Cost Savings – Reduced maintenance and retightening frequency translate to lower operational costs over the product lifecycle.
Traceability and Quality Assurance – With Mill Test Reports, you can verify the exact material grade and mechanical properties, meeting rigorous quality standards for export or critical applications.
Reliable Supply Chain – As a manufacturer with over 25 years of experience, we offer stable production capacity, consistent quality, and on-time delivery.

At Anping County Boli Hardware Wiremesh Products Factory, we have been serving global customers since 1998. Our annual export value exceeds US$5 million – US$10 million, with products shipped to major markets including North America, South America, Europe, Southeast Asia, Africa, Oceania, the Middle East, and Asia. Our ports of shipment are Tianjin, Qingdao, Shanghai, and Foshan, ensuring convenient logistics for international buyers. We are committed to providing high-quality fasteners backed by excellent customer service. With our 12-month warranty and Mill Test Report, you can purchase with confidence. Contact us today to request a quote, sample, or custom specification – we are ready to support your project from start to finish.

Frequently Asked Questions (FAQ)

What is a double coil spring washer? – A double coil spring washer is a type of lock washer that features two coils (or two turns) of spring steel, providing higher elastic force and better vibration resistance compared to single coil washers. It is often used in applications where loosening due to dynamic loads is a concern.
What is the difference between a double coil and a single coil spring washer? – The double coil design increases the spring deflection and load capacity, offering more effective locking action. Single coil washers are suitable for lighter loads, while double coil washers are preferred for heavy-duty or critical assemblies.
What does the Mill Test Report (MTR) include? – The Mill Test Report provides chemical composition analysis, mechanical properties (tensile strength, hardness, yield strength), and heat treatment details. It ensures that the material meets the specified grade and standards.
Does the 12-month warranty cover all defects? – The warranty covers manufacturing defects such as material flaws, dimensional inaccuracies, or improper heat treatment. It does not cover damage caused by misuse, improper installation, or environmental conditions outside the product's specification. Please refer to our terms and conditions for details.
Can you produce washers in non-standard sizes? – Yes, we offer customization for dimensions, materials, and surface treatments. Simply provide your drawing, sample, or technical requirements, and our engineering team will work with you to produce the exact product.
What is the minimum order quantity (MOQ)? – For standard sizes, MOQ is typically 5,000 pieces. For custom sizes, MOQ may vary depending on the complexity and material. Please contact our sales team for a precise quote.
How long is the lead time? – For standard sizes and finishes, lead time is 7–15 working days after order confirmation. For custom orders, it may take 15–25 working days, depending on the production schedule and material availability.
How are the washers packaged? – Standard packaging is in cartons and then on pallets, suitable for export. We can also customize packaging (e.g., small boxes, poly bags, or bulk packing) according to your requirements.