This is the Craft Spring Hardware Collection from BQUQ — a full line of custom compression, extension, torsion, and constant-force springs built for precision manufacturing. You get a tolerance of ±0
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This is the Craft Spring Hardware Collection from BQUQ — a full line of custom compression, extension, torsion, and constant-force springs built for precision manufacturing. You get a tolerance of ±0
This is the Craft Spring Hardware Collection from BQUQ — a full line of custom compression, extension, torsion, and constant-force springs built for precision manufacturing. You get a tolerance of ±0.01 mm on wire diameter, a runout of 0.02 mm TIR, and a surface finish of Ra 0.4 µm, all shipped within 7 days for prototypes and 15 days for production runs. Every spring is made in China at our 20-year-old Dongguan factory, and we offer a no MOQ policy so you can test one piece before committing to volume.
Wire diameter is the first thing that fails on cheap springs. We solve it by using CNC coiling machines with closed-loop laser gauging that measures every coil as it forms. The system adjusts tension in real time, so you get a consistent wire diameter of 0.1 mm to 12 mm without the drift you see from mechanical stops. For example, a 2.0 mm wire stays at 2.000 mm ±0.01 mm across a 10,000-piece batch. That repeatability matters when your assembly uses a spring as a locating feature or a contact point.
Runout is the silent killer in rotating or reciprocating assemblies. We grind both end coils flat and parallel, then check each spring on a V-block with a dial indicator. Our maximum total indicated runout is 0.02 mm TIR for springs up to 50 mm in free length. That is not a best-case number — it is the worst we ship. If your application has a tight bore, this runout prevents binding and uneven wear, which extends the life of your mechanism.
We stock five spring-grade materials in-house: music wire (ASTM A228), oil-tempered chrome silicon (ASTM A401), stainless steel 302 (ASTM A313), 17-7 PH (ASTM A313), and Inconel X-750 for high-temperature work. Heat treatment is done in a controlled atmosphere furnace to prevent decarburization. Chrome silicon springs are hardened to 48–52 HRC, while music wire runs 45–50 HRC. We stress-relieve every part after coiling, and for critical applications we can add shot peening to improve fatigue life by up to 300%.
Surface finish is not just cosmetic. Cracks start at surface imperfections. Our standard finish is Ra 0.4 µm, achieved by tumbling or centerless grinding on the OD. For high-cycle applications, we offer shot peening with ceramic media to induce compressive stress. This is measurable: a spring that lasts 100,000 cycles unpeened will last 300,000 cycles peened. We also offer passivation for stainless steel to meet ASTM A967, which removes free iron and prevents corrosion.
Every spring in the Craft Spring Hardware Collection goes through a 5-step check before it leaves our floor. First, we measure free length and solid height with a digital height gauge. Second, we test load at a specified deflection using a load cell with 0.1 N resolution. Third, we check OD and ID with a pin gauge. Fourth, we verify runout on a V-block. Fifth, we do a 100% visual inspection under magnification for surface defects. You get a dimensional report with every order, and we keep records for 10 years in case of a field failure.
Most Chinese factories quote 20 days because they batch orders. We do the opposite — we run single-piece flow on our CNC coilers. This means your prototype ships in 7 days and production runs of up to 5,000 pieces ship in 15 days. We keep 20 tons of wire in stock across all five materials, so we never wait for raw material. If you need an emergency order, we can ship a single spring in 48 hours via DHL, but that is an extra service, not the standard.
We see three failures in customer-supplied springs: set (permanent deformation), fatigue cracking, and corrosion. Set is eliminated by using a higher grade material than the application requires — for example, using chrome silicon instead of music wire when the operating temperature exceeds 80°C. Fatigue is addressed by shot peening and by designing for a stress level below 50% of the material’s tensile strength. Corrosion is handled by choosing stainless or passivated carbon steel. Send us your load and deflection requirements, and we will tell you which material and finish to use. For a deeper look at how tooling and tolerances affect your parts, see our CNC cutting tool selection guide and our CNC machining tolerances guide.
| Specification | Value |
|---|---|
| Wire diameter range | 0.1 mm – 12.0 mm |
| Maximum free length | 150 mm (longer on request) |
| Outside diameter range | 1.0 mm – 80.0 mm |
| Materials | Music wire, chrome silicon, SS302, 17-7 PH, Inconel X-750 |
| Hardness (chrome silicon) | 48–52 HRC |
| Hardness (music wire) | 45–50 HRC |
| Wire diameter tolerance | ±0.01 mm |
| Runout (TIR) | 0.02 mm max |
| Surface finish | Ra 0.4 µm standard, Ra 0.2 µm optional |
| Load tolerance | ±3% at specified deflection |
| Prototype lead time | 7 days |
| Production lead time | 15 days (up to 5,000 pcs) |
| MOQ | No MOQ — order 1 piece or 100,000 |
No MOQ — we accept a single prototype unit for testing before you commit to production.
Yes, we make conical, barrel, hourglass, and variable-pitch springs with custom ends (closed, ground, or looped) based on your CAD file.
We use SPC monitoring on wire diameter and load, with a CpK of 1.33 or higher, and we include a full dimensional report with every shipment.
Prototype ships in 7 days, and production of up to 5,000 pieces ships in 15 days from drawing approval.
Ready to test the Craft Spring Hardware Collection? Send your drawing or specify load, deflection, and environment. We will reply with a firm quote within 12 hours. Email your file to sc@bquq.com or message us on WhatsApp at +86 13713157787. No MOQ, no waiting — your custom spring starts today.
| 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 |
