{"product_id":"305mm-long-compression-spring-18mm-80mm-diameter-pressure-coiled-springs","title":"305mm Long Compression Spring 18mm - 80mm Diameter，Pressure- coiled springs","description":"\u003cdiv class=\"hdiy-desc\"\u003e\n\u003cdiv class=\"hdiy-overview\"\u003e\n\u003ch2\u003e305mm Long Compression Springs — Reliable Coil Force for CNC, Automation \u0026amp; DIY\u003c\/h2\u003e\n\u003cp\u003eEngineers, makers, and DIY builders who need a dependable compression spring for load-bearing or return-force applications often struggle to find a single source that covers the full range of wire diameters and outer diameters in one consistent length. These 305mm long compression coil springs are designed for exactly that — a standardized free length that fits a wide variety of mechanical assemblies without custom fabrication.\u003c\/p\u003e\n\u003cp\u003eEach spring is wound from round wire stock with a free length of 305mm (approximately 12 inches). Wire diameters span 4mm to 14mm and outer diameters range from 18mm to 90mm (roughly 0.71\" to 3.54\"). Two material options are available: spring steel for general-purpose mechanical use, and stainless steel for environments requiring enhanced corrosion resistance. End coils are closed and ground for flat, stable seating.\u003c\/p\u003e\n\u003cp\u003eTypical applications include CNC router Z-axis return mechanisms, industrial press tooling, robotic arm counterbalance assemblies, agricultural equipment linkages, and heavy-duty drawer or gate return systems — all scenarios where a consistent 305mm free length and precise wire-to-OD ratio are critical for predictable spring rate performance.\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, guide rods, and bores sized to match the selected outer diameter. Verify inner diameter clearance against your guide rod OD before ordering. Closed and ground ends ensure flat seating on machined surfaces.\u003c\/div\u003e\n\u003ch2\u003e✅ Key Features of These 305mm Compression Coil Springs\u003c\/h2\u003e\n\u003cdiv class=\"hdiy-features\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"hdiy-icon\"\u003e📏\u003c\/div\u003e\n\u003cstrong\u003eFixed 305mm Free Length\u003c\/strong\u003e\n\u003cp\u003eConsistent 305mm (≈12\") free length across all variants simplifies design calculations and drop-in replacement for standard mechanical assemblies.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"hdiy-icon\"\u003e🔩\u003c\/div\u003e\n\u003cstrong\u003eWide Diameter Range\u003c\/strong\u003e\n\u003cp\u003eWire diameters from 4mm to 14mm paired with outer diameters from 18mm to 90mm give you precise spring rate control across light to heavy-load applications.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"hdiy-icon\"\u003e🛡️\u003c\/div\u003e\n\u003cstrong\u003eTwo Material Options\u003c\/strong\u003e\n\u003cp\u003eChoose spring steel for cost-effective general use or stainless steel for corrosion-resistant performance in humid, outdoor, or washdown environments.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"hdiy-icon\"\u003e🔄\u003c\/div\u003e\n\u003cstrong\u003eClosed \u0026amp; Ground Ends\u003c\/strong\u003e\n\u003cp\u003eBoth ends are closed and ground flat, ensuring stable, perpendicular seating on spring plates and machined bores — reducing lateral deflection under load.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"hdiy-icon\"\u003e⚡\u003c\/div\u003e\n\u003cstrong\u003eConsistent Coil Pitch\u003c\/strong\u003e\n\u003cp\u003eUniform coil pitch throughout the active coil length delivers linear force-deflection behavior, making these springs predictable for engineering calculations.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"hdiy-icon\"\u003e🏭\u003c\/div\u003e\n\u003cstrong\u003eBroad Application Fit\u003c\/strong\u003e\n\u003cp\u003eSuited for CNC machines, robotic actuators, press tooling, agricultural linkages, and heavy-duty return mechanisms where a standardized 305mm spring is required.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003ch2\u003e📐 Technical Specifications — Compression Coil Springs\u003c\/h2\u003e\n\u003cdiv class=\"hdiy-table-wrap\"\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eFree Length\u003c\/th\u003e\n\u003ctd\u003e305 mm (≈ 12.0 in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eWire Diameter Range\u003c\/th\u003e\n\u003ctd\u003e4 mm – 14 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eOuter Diameter Range\u003c\/th\u003e\n\u003ctd\u003e18 mm – 90 mm (≈ 0.71\" – 3.54\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eInner Diameter\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eMaterial\u003c\/th\u003e\n\u003ctd\u003eSpring steel \/ Stainless steel (see variant options)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eEnd Type\u003c\/th\u003e\n\u003ctd\u003eClosed and ground\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eCoil Direction\u003c\/th\u003e\n\u003ctd\u003eRight-hand\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\u003eSurface Finish\u003c\/th\u003e\n\u003ctd\u003eNatural \/ uncoated\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eQuantity per Order\u003c\/th\u003e\n\u003ctd\u003e1 pcs (see variant options)\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 outer diameter for my application?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eMeasure the inner diameter of your spring housing or bore, then select an outer diameter (OD) that provides a small clearance — typically 0.5mm to 2mm smaller than the bore ID. If you are using a guide rod, the spring's inner diameter (OD minus 2× wire diameter) should be at least 0.5mm larger than the rod OD to allow free movement without binding.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eWhat is the difference between spring steel and stainless steel variants?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eSpring steel offers a higher elastic modulus and is the standard choice for dry, indoor mechanical applications where cost efficiency matters. Stainless steel provides significantly better corrosion resistance, making it the right choice for outdoor equipment, food-processing machinery, marine environments, or any application exposed to moisture, chemicals, or humidity over time.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eAre these springs suitable for CNC router or 3D printer Z-axis assemblies?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eYes. The 305mm free length and closed-ground ends make these springs well-suited for CNC router Z-axis return mechanisms and bed-leveling spring assemblies on larger 3D printers. Select a wire diameter and OD combination that matches your guide rod diameter and the load your axis needs to counterbalance. The linear spring rate behavior supports repeatable positioning.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eHow strong are these compression springs — what loads can they handle?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eLoad capacity varies by wire diameter and outer diameter combination. Larger wire diameters (e.g., 10mm–14mm) with smaller OD-to-wire-diameter ratios produce stiffer springs capable of handling heavier loads. Lighter wire diameters (4mm–5mm) are suited for lighter return-force applications. For precise spring rate and load data for a specific variant, contact us to confirm before ordering for critical load-bearing applications.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eDo the closed and ground ends matter for my installation?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eYes — closed and ground ends ensure the spring sits flat and perpendicular on its seat. This reduces lateral (side) deflection under compression, which is important for maintaining alignment in guided spring assemblies. If your application uses a spring plate or machined pocket, ground ends provide a stable, consistent contact surface that unground ends cannot.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eCan I use these springs in outdoor or corrosive environments?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eFor outdoor or corrosive environments, select the stainless steel material option. Stainless steel compression springs resist rust and oxidation in humid, wet, or mildly chemical environments. Spring steel variants are not recommended for prolonged outdoor exposure without additional protective coating, as they can develop surface rust over time.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eWhat should I check before ordering to ensure the spring fits my assembly?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eVerify three dimensions: (1) free length — confirm 305mm fits your uncompressed travel space; (2) outer diameter — must clear your housing bore with a small gap; (3) inner diameter (OD minus 2× wire dia) — must slide freely over your guide rod if one is used. Also confirm the compressed length at your maximum deflection does not reach solid height, which would cause coil bind and potential damage.\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 Material above, then add to cart.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cp\u003e \u003c\/p\u003e","brand":"HomeDIYer","offers":[{"title":"4 x18 x305 mm \/ Spring steel \/ 1 pcs","offer_id":52449302774034,"sku":"LXX6DFQ6329x1","price":12.63,"currency_code":"USD","in_stock":true},{"title":"4 x20 x305 mm \/ Spring steel \/ 1 pcs","offer_id":52449302806802,"sku":"LXX6DFQ6345x1","price":12.72,"currency_code":"USD","in_stock":true},{"title":"4 x22 x305 mm \/ Spring steel \/ 1 pcs","offer_id":52449302839570,"sku":"LXX6DFQ6373x1","price":13.11,"currency_code":"USD","in_stock":true},{"title":"4 x25 x305 mm \/ Spring steel \/ 1 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