This is BQUQ’s Steel Torsion Spring Collection — a family of custom torsion springs CNC-formed from certified spring steel, built for cyclic deflection and torque repeatability. Yo
Steel Torsion Spring Collection | Custom Precision Springs by BQUQ
This is BQUQ’s Steel Torsion Spring Collection — a family of custom torsion springs CNC-formed from certified spring steel, built for cyclic deflection and torque repeatability. You get ±0.05 mm free
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This is BQUQ’s Steel Torsion Spring Collection — a family of custom torsion springs CNC-formed from certified spring steel, built for cyclic deflection and torque repeatability. You get ±0.05 mm free angle tolerance, a consistent surface finish of Ra 0.8, and a hardness range of 45–52 HRC, with a standard lead time of 7 days from drawing approval.
We have run this exact process for 20 years in our Dongguan factory — over 12,000 torsion spring orders shipped. Every coil is set-tested before leaving the floor. No MOQ, no minimum order friction, no guesswork on your prototype or production run.
How We Control Torque Within ±3% of Your Specified Load
Torsion springs fail when the residual stress is not properly relieved after forming. We use a two-stage stress-relief bake at 260°C for 30 minutes after coiling, then another 20-minute cycle after leg bending. This stabilizes the material and holds your torque within ±3% of the load you specify at any given deflection angle.
For critical applications, we add a preset operation — compressing the spring to solid height three times before shipping. This eliminates initial settling and gives you predictable torque from the first cycle. We measure the actual torque on a calibrated torsion tester at 15°, 30°, and 45° deflection, and we include that data sheet with every batch.
Materials and Heat Treatment We Use for Long Fatigue Life
We stock four grades of spring steel: SWP-A (music wire) for small sections under 2.0 mm, SWOSC-V (chrome vanadium) for high stress and elevated temperatures up to 120°C, SUS304-WPB (stainless) for corrosive environments, and 65Mn (carbon steel) for cost-sensitive large runs. Wire diameters range from 0.2 mm to 12.0 mm.
Heat treatment is not an afterthought. We austenitize at 830°C for chrome vanadium, oil quench, then temper at 420°C to reach 45–52 HRC. Stainless springs are precipitation-hardened at 480°C for 1 hour. Every heat lot is Rockwell-tested on the C-scale, and a hardness report is attached to your shipment.
Leg Bending, End Configurations, and Free Angle Precision
Your drawing defines the legs — straight, hooked, or hinged. We bend legs on a CNC 5-axis former, not a manual jig. This gives us a leg position tolerance of ±0.3 mm and a free angle tolerance of ±2 degrees on standard parts, tightening to ±1 degree on request.
We also handle double torsion springs with a center gap from 0.5 mm to 50 mm. Our CNC coiling machines hold the pitch and outer diameter consistently across the entire length. If your design demands a closed end, we grind the last coil flat within 0.05 mm of perpendicularity.
Inspection Before Every Shipment — What We Measure and Why
Every torsion spring batch goes through a four-step inspection protocol. First, we measure outer diameter and free length with a digital micrometer (resolution 0.001 mm). Second, we check the free angle on a comparator screen with a ±0.5° resolution. Third, we set the spring to your specified deflection and measure the torque on a digital tester with a 0.1 N·mm resolution.
Fourth, we run a fatigue check on a sample of 5 pieces per batch, cycling to your max deflection for 10,000 cycles. If any sample cracks or loses more than 5% of its initial torque, the whole batch is rejected and re-run. You get a full inspection report with photographs of the measured parts, not just a certificate.
Surface Protection Options That Match Your Environment
Bare steel torsion springs rust. We offer three standard finishes: zinc-plated (blue or yellow, 8–12 µm thickness, salt spray tested to 72 hours), black oxide (for dry interior applications, 0.5 µm thickness), and electroless nickel plating (for marine or chemical exposure, 15–20 µm thickness, 200 hours salt spray).
For stainless steel springs, we offer electropolishing to remove surface micro-cracks and improve fatigue life by up to 30%. We also apply dry-film lubrication (molybdenum disulfide or PTFE) on the wire surface to reduce friction between coils during deflection — this is critical for high-cycle applications above 100,000 cycles.
Why a Dedicated Fixture Beats a Universal Coiler for Your Leg Geometry
Universal CNC coilers are fast, but they struggle with complex leg bends in two planes. For torsion springs with an offset leg or a 90-degree radial bend, we build a dedicated bending fixture on a wire EDM machine. This fixture positions the leg within ±0.05 mm, regardless of wire diameter.
The fixture cost is amortized into your first order — typically $50 to $150 depending on complexity. It is then stored in our tooling library and reused for every repeat order at no extra cost. This is why our repeat customers see identical part geometry across orders placed six months apart.
Production Capacity and Realistic Lead Times for Prototype and Bulk
Our factory floor runs 18 CNC coiling machines and 12 CNC leg benders, 24 hours a day, 5 days a week. Prototype orders (up to 100 pieces) ship in 5–7 days. Medium runs (100–5,000 pieces) ship in 7–10 days. Production runs above 5,000 pieces ship in 12–15 days, depending on heat treatment capacity.
We keep a buffer of 500 kg of SWP-A and 300 kg of SWOSC-V in stock at all times, so material procurement never delays your order. Rush service is available for an additional 20% surcharge — your prototype ships in 72 hours.
Parameter
Value / Range
Wire diameter
0.2 – 12.0 mm
Outer diameter (max)
150 mm
Free length (max)
300 mm
Total coils
2 – 50
Free angle tolerance
±2° standard, ±1° on request
Torque tolerance
±3% of specified load
Hardness
45 – 52 HRC (carbon & alloy steel)
Surface finish
Ra 0.8 µm (as formed), Ra 0.4 µm (ground ends)
Max working temperature
120°C (chrome vanadium), 250°C (stainless 17-7PH)
Lead time (prototype)
5 – 7 days
Lead time (production)
12 – 15 days
MOQ
No MOQ — 1 piece accepted
Common Failure Modes We Prevent in Your Design
Most torsion spring failures come from three mistakes: wrong direction of coiling, missing leg clearance at solid height, and insufficient stress relief. We check your drawing for coil direction (left-hand vs right-hand) against your torque direction — we will flag it if you specify it wrong, before quoting.
We also simulate the solid height condition in CAD and confirm that adjacent coils do not bind before the required deflection angle. If they do, we suggest a reduced coil count or a larger wire pitch. This proactive check has saved our customers from field failures in 47 documented cases over the past two years.
What is the minimum order quantity for a custom torsion spring?
There is no MOQ — we accept a single prototype piece for testing, and the per-piece price drops naturally as your order quantity increases.
Can you match a torsion spring from a competitor or an OEM part?
Yes, send us the sample or its dimensions, and we will reverse-engineer it — measuring wire diameter, coil count, free angle, and torque — then quote you a replacement within 48 hours.
How do you guarantee the torque value on a production run?
We test torque on every batch at three deflection angles and include the test data sheet with the shipment; if any spring is out of the ±3% band, it is replaced at no cost.
What is the fastest way to get a quote for my torsion spring drawing?
Email your drawing (STEP, PDF, or DXF) to sc@bquq.com or send it via WhatsApp to +86 13713157787 — you receive a firm quote with a delivery date within 12 business hours.
For the best spring geometry, pair your design with the right tooling — check our CNC cutting tool selection guide if you are also machining the mating parts. To understand the dimensional limits we hold on every order, read the CNC machining tolerances guide.
Send your torsion spring drawing today. You get a firm quote within 12 hours, with exact pricing, tooling cost (if any), and a confirmed delivery date. Email sc@bquq.com or WhatsApp +86 13713157787. Precision manufacturing, made in China, with no MOQ and a 20-year track record.
