What This Collection Delivers in Hard Numbers This is a Stainless Steel Compression Spring Collection built for engineers who need repeatable force and geometry in tight assemblies. You get wire diam
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What This Collection Delivers in Hard Numbers This is a Stainless Steel Compression Spring Collection built for engineers who need repeatable force and geometry in tight assemblies. You get wire diam
This is a Stainless Steel Compression Spring Collection built for engineers who need repeatable force and geometry in tight assemblies. You get wire diameters from 0.1 mm to 8.0 mm, free length tolerances of ±0.01 mm, and outer diameter runout under 0.02 mm. Lead time is 15 days for prototypes, 25 days for production runs, and hardness is controlled between 42 and 52 HRC depending on grade.
We are BQUQ, a precision manufacturing factory in Dongguan, China, with 20 years of CNC machining, stamping, and spring coiling experience. Every spring is made to your drawing, not from a catalog.
We stock 302, 304, 316L, and 17-7PH stainless steel wire. For high-temperature or corrosive environments, 316L is the default choice. For higher fatigue life, we use 17-7PH and precipitation harden it to 47-52 HRC.
Heat treatment is done in-house in controlled atmosphere furnaces. We set the temperature profile based on wire diameter and free length ratio. This removes residual stress from coiling and sets the spring's load curve. Each batch gets a hardness test on three samples, not one.
Free length tolerance is the most common failure point in custom springs. Our CNC coilers measure wire feed and pitch in real time, then we verify with optical comparators. For springs under 50 mm free length, we hold ±0.01 mm. For longer springs, we hold ±0.02 mm.
Load at a specified deflection is tested on a calibrated compression tester. We report load values at 25%, 50%, and 75% of total deflection on every inspection sheet. If your design requires a specific spring rate (N/mm), we calculate that from the measured load curve, not from theoretical formulas.
Closed and ground ends are standard for this collection. We grind both ends flat and parallel to the spring axis. Squareness is held within 1 degree, which prevents buckling and uneven load distribution in your assembly.
For springs with a free length to mean diameter ratio above 4:1, we add extra grinding passes. This reduces the risk of side thrust and premature fatigue. Surface finish after grinding is Ra 0.4 µm on the bearing surfaces.
Every spring is checked for wire diameter, outer diameter, free length, and total coils. We use a digital caliper with 0.001 mm resolution and a toolmaker's microscope for wire profile.
Load testing is done on a 5 kN universal tester with a deflection accuracy of ±0.01 mm. We sample 100% for critical dimensions on orders under 500 pieces. For larger orders, we use AQL 0.65 sampling per ISO 2859-1. Each shipment includes a material certificate with mill traceability and a dimensional report.
Standard finish is as-coiled with a light oil film. For cleanroom or medical use, we offer electropolishing to Ra 0.2 µm. This removes micro-cracks and improves corrosion resistance.
Passivation to ASTM A967 is available. This removes free iron from the surface and enhances the chromium oxide layer. If your spring will be in a salt spray environment, specify passivation plus electropolishing. We have tested this combination to 500 hours in a 5% salt spray chamber without red rust.
Send us a PDF or STEP file. We review your spring rate, solid height, and buckling risk within 4 hours. If the design is borderline, we call you to discuss, not just email.
We build prototypes in 3-5 days using the same wire and heat treatment as production. This eliminates scale-up surprises. For production, we use the same CNC coilers and same operators, so tolerances do not drift.
We export worldwide. Most shipments go via DHL, FedEx, or UPS from our Shenzhen warehouse. For large orders, we use sea freight from Yantian port. Customs documentation is handled in-house.
| Parameter | Specification / Range |
|---|---|
| Wire diameter | 0.1 mm – 8.0 mm |
| Free length | 2 mm – 300 mm |
| Outer diameter | 1.0 mm – 80 mm |
| Materials | 302, 304, 316L, 17-7PH stainless steel |
| Hardness | 42 – 52 HRC (depending on grade and heat treatment) |
| Free length tolerance | ±0.01 mm (under 50 mm), ±0.02 mm (over 50 mm) |
| Outer diameter runout | ≤ 0.02 mm |
| Squareness | ≤ 1 degree |
| Surface finish (ground ends) | Ra 0.4 µm; electropolished to Ra 0.2 µm on request |
| Load tolerance | ±3% of specified load at a given deflection |
| Lead time | 15 days prototypes, 25 days production |
| MOQ | No MOQ – order 1 piece or 100,000 pieces |
Compression springs are often used alongside precision machined parts. If you are designing a spring-loaded mechanism, the spring rate must match the machining tolerances of your housing. To ensure your mating components are within spec, check our CNC machining tolerances guide for a practical breakdown of IT grades and surface finish limits.
If your spring is part of a cutting tool assembly, such as a tool holder or a collet closer, the spring's force curve interacts with the tool's geometry. For choosing the right tool material and coating, read our CNC cutting tool selection guide to avoid stiffness mismatches.
No MOQ. You can order one prototype for validation, and we will run it on the exact same production line as a 100,000-piece order.
Send a drawing with wire diameter, free length, outer diameter, and required load at a specific deflection; we will confirm feasibility and suggest a material grade based on your environment.
We measure every critical dimension on 100% of small orders and use AQL 0.65 sampling for large orders, with load testing, hardness checks, and an optical comparator report included with shipment.
Prototypes ship in 15 days, production orders in 25 days after drawing approval, and we can expedite prototypes to 5 days for urgent validation if you contact us directly.
Send us your drawing, load requirements, and annual quantity. We will reply with a firm quote, DFM feedback, and a sample plan within 12 business hours. This is a precision manufacturing service made in China, but with engineering communication in clear English.
Email: sc@bquq.com
WhatsApp: +86 13713157787
Send your drawing today. We will tell you if it can be made better, cheaper, or faster.
| Parameter | Capability |
|---|---|
| Materials | SUS302/304/316, SWC piano wire, SWP music wire, 65Mn, phosphor bronze, beryllium copper |
| Types | Compression, extension, torsion, wire forms, battery springs, touch springs |
| Wire Diameter | 0.05 - 12.0 mm |
| Tolerance | ±0.02mm standard, ±0.01mm on request |
| Surface | Zinc plating, nickel, black oxide, passivation, shot peening |
| Machines | CNC spring coiling machines, torsion machines, wire forming machines |
| Prototype | 72 hours, no MOQ on samples |
| Inspection | Load test per batch, fatigue test data on request |
