{"product_id":"compression-spring-steel-black-treatment-3-6mm-wire-dia-305-400mm-length","title":"Compression Spring Steel With Black Treatment 3~6mm Wire Dia \u0026 305~400mm Length","description":"\u003cdiv class=\"hdiy-desc\"\u003e\n\u003cdiv class=\"hdiy-overview\"\u003e\n\u003ch2\u003eCompression Spring Steel with Black Oxide Treatment — Reliable Force Control for DIY and Industrial Applications\u003c\/h2\u003e\n\u003cp\u003eWhen a project demands consistent return force, vibration damping, or load-bearing resilience, a poorly matched spring becomes the weakest link in the assembly. Whether you are a maker building a custom press, a technician maintaining industrial equipment, or a hobbyist designing a mechanical linkage, these compression spring steel components deliver the dimensional accuracy and surface protection needed to keep your build running reliably.\u003c\/p\u003e\n\u003cp\u003eEach spring is formed from carbon steel wire and finished with a black oxide treatment that provides a uniform dark coating across the coil surface. Wire diameters span 2.3 mm to 6 mm (approximately 0.09 in to 0.24 in), outer diameters range from 14 mm to 50 mm (approximately 0.55 in to 1.97 in), and free lengths are available in 305 mm (approximately 12.0 in) and 400 mm (approximately 15.7 in) options. Quantity options of 1, 2, or 5 pieces per order allow you to stock exactly what you need.\u003c\/p\u003e\n\u003cp\u003eTypical use cases include compression spring replacement in mechanical presses and stamping fixtures, return-force elements in DIY automation jigs and robotic end-effectors, and load-bearing cushioning in custom furniture hardware or drawer-slide mechanisms — all scenarios where a black oxide compression spring with a defined wire diameter and free length simplifies sourcing and assembly.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"hdiy-compat\"\u003e\n\u003cspan class=\"hdiy-compat-icon\"\u003e⚙️\u003c\/span\u003e \u003cstrong\u003eCompatibility:\u003c\/strong\u003e Suitable for standard spring seats and bores sized to match the selected outer diameter. Verify bore clearance and seat recess depth against your chosen variant before installation.\u003c\/div\u003e\n\u003cdiv class=\"hdiy-features\"\u003e\n\u003ch2\u003e✅ Key Features of These Compression Spring Steel Components\u003c\/h2\u003e\n\u003cul class=\"hdiy-list\"\u003e\n\u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🔩\u003c\/span\u003e \u003cstrong\u003eCarbon Steel Construction\u003c\/strong\u003e — Formed from carbon steel wire for consistent spring-back force and resistance to permanent set under repeated compression cycles.\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🖤\u003c\/span\u003e \u003cstrong\u003eBlack Oxide Surface Treatment\u003c\/strong\u003e — The black treatment provides a uniform corrosion-inhibiting layer that reduces surface oxidation in low-humidity indoor environments and gives a clean, finished appearance.\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e📐\u003c\/span\u003e \u003cstrong\u003eWide Size Range\u003c\/strong\u003e — Wire diameters from 2.3 mm to 6 mm and outer diameters from 14 mm to 50 mm cover a broad spectrum of spring seat sizes, reducing the need for custom fabrication.\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e📏\u003c\/span\u003e \u003cstrong\u003eTwo Free-Length Options\u003c\/strong\u003e — Available in 305 mm and 400 mm free lengths, giving you flexibility to cut to length or use as-is depending on your travel and preload requirements.\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🔢\u003c\/span\u003e \u003cstrong\u003eFlexible Quantity Packs\u003c\/strong\u003e — Order 1, 2, or 5 pieces per variant so you can prototype with a single spring or stock a small batch without over-ordering.\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🏭\u003c\/span\u003e \u003cstrong\u003eBroad Application Fit\u003c\/strong\u003e — Suited for mechanical presses, automation jigs, robotic assemblies, furniture hardware, and general-purpose DIY machinery where a defined compression spring with black oxide finish is specified.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"hdiy-table-wrap\"\u003e\n\u003ch2\u003e📐 Technical Specifications — Compression Spring Steel\u003c\/h2\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eMaterial\u003c\/th\u003e\n\u003ctd\u003eCarbon steel\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eSurface Finish\u003c\/th\u003e\n\u003ctd\u003eBlack oxide treatment\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eWire Diameter Range\u003c\/th\u003e\n\u003ctd\u003e2.3 mm – 6 mm (0.09 in – 0.24 in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eOuter Diameter Range\u003c\/th\u003e\n\u003ctd\u003e14 mm – 50 mm (0.55 in – 1.97 in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFree Length Options\u003c\/th\u003e\n\u003ctd\u003e305 mm (12.0 in) \/ 400 mm (15.7 in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eWire Dia × OD × Length\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eSpring Rate\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eEnd Type\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eCoil Direction\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eQuantity per Order\u003c\/th\u003e\n\u003ctd\u003e1 \/ 2 \/ 5 pieces (select above)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eApplication Type\u003c\/th\u003e\n\u003ctd\u003eCompression\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"hdiy-faq\"\u003e\n\u003ch2\u003e❓ Frequently Asked Questions\u003c\/h2\u003e\n\u003cdetails\u003e\n\u003csummary\u003eHow do I choose the right wire diameter and outer diameter for my application?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eStart with the bore or spring seat in your assembly. The outer diameter of the spring must fit freely inside the bore with a small clearance (typically 1–2 mm on each side). Then select a wire diameter that delivers the load and deflection you need — thicker wire produces a stiffer spring with higher load capacity. If you are unsure, measure your existing spring or consult a spring rate calculator using the outer diameter, wire diameter, and number of active coils.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eWhat load capacity can I expect from these springs?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eLoad capacity depends on the specific wire diameter, outer diameter, free length, and number of active coils of each variant. Carbon steel compression springs in the 2.3–6 mm wire diameter range typically handle light to medium loads suitable for jigs, fixtures, and general machinery. For precise spring rate and maximum load data, contact us with your selected variant dimensions and we can provide further guidance.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eDoes the black oxide treatment protect against rust and corrosion?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eBlack oxide is a conversion coating that provides mild corrosion resistance by reducing the rate of surface oxidation. It performs well in dry indoor environments. For outdoor use, high-humidity conditions, or exposure to chemicals, consider applying a light coat of oil or grease after installation to extend service life. If your application requires stronger corrosion protection, look for stainless steel or zinc-plated spring options.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eCan I cut these springs to a shorter free length?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eYes, carbon steel compression springs can be cut to a shorter free length using an angle grinder or spring cutter. After cutting, grind the end coil flat to restore a proper bearing surface. Keep in mind that cutting changes the number of active coils, which alters the spring rate — a shorter spring from the same wire and OD will be stiffer. Plan your cut length carefully based on your required travel and preload.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eAre these springs compatible with standard spring guides and mandrels?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eYes. These springs are designed with standard coil geometry and can be used with inner mandrels (guide rods) or outer guide bores. For inner mandrel use, the mandrel diameter should be slightly smaller than the spring's inner diameter (outer diameter minus twice the wire diameter) to allow free compression without binding. Check the inner diameter of your selected variant before specifying a mandrel size.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eWhich variant should I choose for a 305 mm vs 400 mm length application?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eChoose the free length that matches or slightly exceeds your required installed length plus maximum compression travel. The 305 mm variants are well-suited for compact assemblies and shorter stroke applications, while the 400 mm variants provide more travel range or allow you to cut down to a custom length. Both length families share overlapping wire and outer diameter options, so you can match the same cross-section in either length.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eWhat quantity option should I order for prototyping vs production?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eFor initial prototyping or fit-checking, the single-piece (QTY 1) option lets you validate the spring dimensions and performance in your assembly before committing to more stock. Once confirmed, the 2-piece or 5-piece options offer a lower per-unit cost and ensure you have spares on hand for maintenance or batch builds. Select your quantity in the QTY(PCS) option above alongside your chosen size.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"hdiy-cta\"\u003e🛒 Select your Wire Dia × Outer Dia × Length and QTY above, then add to cart.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cp\u003e \u003c\/p\u003e","brand":"HomeDIYer","offers":[{"title":"3*14*305mm \/ 1","offer_id":52450048409874,"sku":"LXXVKK7501x1","price":4.04,"currency_code":"USD","in_stock":true},{"title":"4*40*305mm \/ 1","offer_id":52450048442642,"sku":"LXXVKK7502x1","price":9.74,"currency_code":"USD","in_stock":true},{"title":"4*45*305mm \/ 1","offer_id":52450048475410,"sku":"LXXVKK7503x1","price":10.01,"currency_code":"USD","in_stock":true},{"title":"5*28*305mm \/ 1","offer_id":52450048508178,"sku":"LXXVKK7504x1","price":9.87,"currency_code":"USD","in_stock":true},{"title":"5*32*305mm \/ 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