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Custom Double Loop Extension Spring | Stainless Steel Industrial Tension Springs
Stainless Steel Double Loop Extension Spring
Heavy-Duty Industrial Tension Springs
What Is an Extension Spring?
Extension springs (tension springs) store energy when stretched and return to their original length when released.
Our double loop end extension springs feature symmetrical closed end hooks on both sides for secure, reliable attachment in industrial, automotive, and hardware applications.
Made from high-grade stainless steel or carbon steel, they deliver consistent tensile force, excellent fatigue resistance, and a long service life—even in high-cycle environments.
Key Features
✅ Premium Material Options
Standard: AISI 304 stainless steel – corrosion resistant, ideal for outdoor & humid conditions
Optional: AISI 316 stainless steel (marine grade) / high carbon steel (heavy-load applications)
✅ Double Loop End Design
Symmetrical closed-loop ends prevent hook deformation and slippage—unlike open hook designs.
✅ Fully Customizable
Wire diameter: 0.2 – 8 mm
Outer diameter: 3 – 100 mm
Free length: 10 – 1000 mm
Tensile force: 5 – 5000 N
Precision-manufactured to your exact dimensional and force requirements.
✅ High Fatigue Resistance
Heat treated and stress relieved. Maintains stable performance over 50,000+ extension cycles without permanent deformation or force loss.
✅ Strict Quality Control
100% dimensional inspection + force testing before shipment. Every spring meets your tolerance and performance standards.
Common Applications
Automotive parts & suspension systems
Industrial machinery & equipment
Garage doors & gate mechanisms
Furniture hardware & recliners
Agricultural equipment
Fitness equipment & gym machines
Marine & outdoor hardware
Why Choose SEME Hardware?
Professional precision spring manufacturer with 10+ years of export experience – OEM & custom springs for factories, distributors, and brands in Europe, North America, and Australia.
🔹 Factory Direct Pricing – No middleman markups
🔹 Low MOQ – From 1,000 pieces; trial orders accepted
🔹 Fast Lead Time – Samples 5–7 days, mass production 10–15 days
🔹 Engineering Support – Help with wire diameter, material & force rating
🔹 Flexible Payment & Shipping – T/T, PayPal, Alipay; DHL/FedEx for samples, sea freight for bulk
How to Order Custom Extension Springs
Please provide the following for an accurate quote:
Wire diameter
Outer diameter
Free length (including hooks)
Required tensile force / load rating
Material preference (304 / 316 / carbon steel)
Order quantity
📩 Our team will reply with a detailed quote and technical recommendation within 24 hours.
Frequently Asked Questions
Q: Can you produce extension springs with other end types?
A: Yes. In addition to double loop ends, we offer open hooks, side hooks, extended hooks, and custom end designs.
Q: Do you provide free samples?
A: Yes – free for standard sizes (shipping cost applies). Custom samples ready in 5–7 days.
Q: What are your spring tolerances?
A: Dimensional: ±0.1mm standard; force: ±10%. Tighter tolerances available upon request.
Q: Can you supply plated or coated springs?
A: Yes. Surface treatments include zinc plating, black oxide, powder coating, and passivation (for carbon steel springs).
Contact Us
Dongguan Seme Precision Hardware Co., Ltd.
📞 Phone / WhatsApp / WeChat: +86 138 2726 4669
📧 Email: [email protected]
🌐 Website: www.semehardware.com
📍 Address: Building 1, No. 48 Minghua Road, Shijie Town, Dongguan City, Guangdong Province, China
👉 Get a free quotation today for your custom extension spring needs!
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