{"product_id":"grade-12-9-socket-head-cap-screws-assortment-m3-m8-high-tensile","title":"Grade 12.9 Socket Head Cap Screws Assortment – M3\/M4\/M5\/M6\/M8 High Tensile Allen Hex Bolts Kit","description":"\u003ch2\u003eGrade 12.9 Socket Head Cap Screws Assortment – M3\/M4\/M5\/M6\/M8 High Tensile Allen Hex Bolts\u003c\/h2\u003e\n\n\u003cp\u003eGrade 12.9 socket head cap screws (SHCS) are the highest-strength standard metric fastener in common use — rated at 1220 MPa tensile strength and 1100 MPa proof load. The socket head (cylindrical head with internal hex drive) allows high torque application in confined spaces where a standard hex bolt head would not fit. This assortment covers the five most commonly used metric sizes (M3 through M8) in multiple lengths, supplied in a labeled storage kit for workshop, CNC, and field use.\u003c\/p\u003e\n\n\u003ch3\u003eKey Specifications\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eStandard:\u003c\/strong\u003e DIN 912 \/ ISO 4762 (socket head cap screw)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGrade:\u003c\/strong\u003e 12.9 (property class per ISO 898-1)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Alloy steel (chromium-molybdenum), black oxide finish\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTensile Strength:\u003c\/strong\u003e 1220 MPa (177,000 PSI)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eProof Load:\u003c\/strong\u003e 1100 MPa\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDrive:\u003c\/strong\u003e Internal hex (Allen key \/ hex socket)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSizes:\u003c\/strong\u003e M3, M4, M5, M6, M8 (multiple lengths per size)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFinish:\u003c\/strong\u003e Black oxide (provides mild corrosion resistance; not suitable for outdoor use without additional protection)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eFastener Grade Comparison — Choosing the Right Strength\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGrade 8.8:\u003c\/strong\u003e 800 MPa tensile. Standard commercial grade. Suitable for general machinery, structural connections, and most automotive applications. Zinc-plated or plain finish.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGrade 10.9:\u003c\/strong\u003e 1040 MPa tensile. High-strength grade for critical joints, engine components, and suspension fasteners. Used where Grade 8.8 is marginal.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGrade 12.9 (this product):\u003c\/strong\u003e 1220 MPa tensile. Maximum standard grade. Used for the most demanding applications: CNC machine tool clamping, high-performance engine components, racing suspension, hydraulic manifold bolting, and precision instrument mounting. Do not substitute with lower grades in Grade 12.9 applications — the joint will yield under design load.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eA2\/A4 Stainless (Grade 70\/80):\u003c\/strong\u003e 700–800 MPa tensile. Corrosion resistant but significantly weaker than Grade 12.9. Never substitute stainless for Grade 12.9 in high-load applications.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat Questions Does This Product Answer?\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cem\u003e\"What Allen key size do I need for M6 Grade 12.9 socket head screws?\"\u003c\/em\u003e — M6 DIN 912 uses a 5mm hex key. M3=2.5mm, M4=3mm, M5=4mm, M6=5mm, M8=6mm. Grade 12.9 screws require a quality hex key — cheap hex keys round out at the high torques required for Grade 12.9 fasteners.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cem\u003e\"What torque should I use for M8 Grade 12.9 socket head screws?\"\u003c\/em\u003e — Typical torque for M8 Grade 12.9 (dry, no lubricant): 40–45 Nm. With thread lubricant (MoS₂ or similar): reduce by 20–25% to avoid over-stressing the fastener. Always use a calibrated torque wrench for critical joints.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cem\u003e\"Can I reuse Grade 12.9 bolts?\"\u003c\/em\u003e — Grade 12.9 bolts can be reused if they have not been torqued beyond yield (i.e., not used as torque-to-yield fasteners). Inspect for thread damage, necking, or head deformation before reuse. Torque-to-yield (TTY) fasteners — common in engine head bolts — must always be replaced.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cem\u003e\"Why are Grade 12.9 screws black instead of silver?\"\u003c\/em\u003e — The black oxide finish is a chemical conversion coating applied after heat treatment. It provides mild corrosion resistance and reduces light reflection. It does not significantly affect strength. For outdoor or corrosive environments, apply a thin film of oil or use zinc-nickel plated Grade 12.9 screws.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cem\u003e\"Can I use Grade 12.9 screws in aluminum?\"\u003c\/em\u003e — Yes, but with caution. The high clamping force of Grade 12.9 fasteners can strip aluminum threads if over-torqued. Use thread inserts (Helicoil, Keensert) in aluminum for Grade 12.9 applications, and reduce torque by 30–40% compared to steel-to-steel values.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTypical Applications\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCNC machining:\u003c\/strong\u003e Workholding clamps, vise jaws, fixture plates, toolholder retention bolts\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAutomotive performance:\u003c\/strong\u003e Engine internals, suspension components, brake caliper bolts, turbocharger mounting\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHydraulics:\u003c\/strong\u003e Manifold block bolting, cylinder end cap fasteners, valve body mounting\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRobotics \u0026amp; automation:\u003c\/strong\u003e Structural frame joints, actuator mounting, high-load pivot points\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePrecision instruments:\u003c\/strong\u003e Optical bench mounting, metrology equipment, coordinate measuring machine (CMM) fixtures\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003ePackage Contents\u003c\/h3\u003e\n\u003cp\u003eAssortment kit — M3, M4, M5, M6, M8 Grade 12.9 socket head cap screws in multiple lengths, supplied in labeled storage case with Allen key.\u003c\/p\u003e","brand":"Cable Parts Online","offers":[{"title":"28 PCS \/ 1 BOX","offer_id":47850767089909,"sku":"14:29#28 PCS;380:201442015#1 BOX","price":82.08,"currency_code":"USD","in_stock":true},{"title":"45PCS \/ 1 BOX","offer_id":47850767057141,"sku":"14:175#45PCS;380:201442015#1 BOX","price":62.41,"currency_code":"USD","in_stock":true},{"title":"48 PCS \/ 1 BOX","offer_id":47850767024373,"sku":"14:366#48 PCS;380:201442015#1 BOX","price":83.27,"currency_code":"USD","in_stock":true},{"title":"110 PCS \/ 1 BOX","offer_id":47850767319285,"sku":"14:10#110 PCS;380:201442015#1 BOX","price":73.05,"currency_code":"USD","in_stock":true},{"title":"150 PCS \/ 1 BOX","offer_id":47850767253749,"sku":"14:200006151#150 PCS;380:201442015#1 BOX","price":48.3,"currency_code":"USD","in_stock":true},{"title":"150 PCS 1 \/ 1 BOX","offer_id":47850767286517,"sku":"14:496#150 PCS;380:201442015#1 BOX","price":51.84,"currency_code":"USD","in_stock":true},{"title":"160 PCS \/ 1 BOX","offer_id":47850767220981,"sku":"14:173#160 PCS;380:201442015#1 BOX","price":37.7,"currency_code":"USD","in_stock":true},{"title":"190 PCS \/ 1 BOX","offer_id":47850767188213,"sku":"14:193#190 PCS;380:201442015#1 BOX","price":49.88,"currency_code":"USD","in_stock":true},{"title":"240 PCS \/ 1 BOX","offer_id":47850767155445,"sku":"14:200005536#240 PCS;380:201442015#1 BOX","price":63.25,"currency_code":"USD","in_stock":true},{"title":"600 PCS \/ 1 BOX","offer_id":47850767122677,"sku":"14:365458#600 PCS;380:201442015#1 BOX","price":83.65,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0732\/3494\/0149\/files\/Sa050fe6981ea49c2ac08955f9e7208fcn.webp?v=1773899653","url":"https:\/\/www.csldmcml.com\/products\/grade-12-9-socket-head-cap-screws-assortment-m3-m8-high-tensile","provider":"Cable Parts Online","version":"1.0","type":"link"}