{"product_id":"m8-8mm-hex-head-coach-screws-bzp","title":"DIYUK M8 (8mm) Hex Head Coach Screws DIN 571, Heavy Duty BZP Timber Fasteners \u0026 Lag Bolts, 30-160mm, 7 Lengths","description":"\u003cp\u003e\u003cstrong\u003eM8 hexagon head coach screws manufactured to DIN 571\u003c\/strong\u003e. Also known as lag screws, lag bolts or hex head wood screws, these heavy-duty fasteners use a hexagon head rather than a slotted or recessed drive, so they can be tightened with a standard spanner or socket for much higher torque than a screwdriver allows – useful wherever a standard wood screw can't generate enough clamping force on its own.\u003c\/p\u003e\n\u003cp\u003eThe screws are manufactured from high-tensile carbon steel and finished with a bright zinc-plated (BZP) coating, giving general-purpose corrosion resistance.\u003c\/p\u003e\n\u003cp\u003eThe coarse, deep wood-screw thread is designed to bite directly into timber, generating high pull-out resistance without needing a nut on the far side – making these screws well suited to structural and semi-structural timber connections. Used with a suitable wall plug, they can also be driven into brick, block or concrete.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eKey Features\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eManufactured to DIN 571, so thread, head and drive sizes are consistent and standard-compliant across every length.\u003c\/li\u003e\n\u003cli\u003eHexagon head accepts a standard spanner or socket rather than a screwdriver, allowing far greater tightening torque – useful for dense or hardwood timber and heavier structural fixings.\u003c\/li\u003e\n\u003cli\u003eHigh-tensile carbon steel construction with a bright zinc-plated (BZP) finish for reliable general-purpose corrosion resistance.\u003c\/li\u003e\n\u003cli\u003eCoarse, deep wood-screw thread bites directly into timber and generates high pull-out resistance without requiring a nut on the reverse face.\u003c\/li\u003e\n\u003cli\u003eAlso known as lag screws or lag bolts, and suited to structural and semi-structural timber-to-timber connections.\u003c\/li\u003e\n\u003cli\u003eAvailable in seven lengths from 30mm (1.18in) to 160mm (6.30in), all sharing the same M8 (8mm \/ 0.31in) thread diameter and 13mm (0.51in) head across flats.\u003c\/li\u003e\n\u003cli\u003eThread length is 60% of the overall screw length on every size, giving a longer grip length as the screw gets longer.\u003c\/li\u003e\n\u003cli\u003eCan be combined with a suitable wall plug to fix into brick, block or concrete as well as solid timber.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eSpecification\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eLength (l)\u003c\/th\u003e\n\u003cth\u003eThread diameter (d)\u003c\/th\u003e\n\u003cth\u003eHead width across flats (s)\u003c\/th\u003e\n\u003cth\u003eHead height (k)\u003c\/th\u003e\n\u003cth\u003eThread length (Lg)\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e30mm (1.18in)\u003c\/td\u003e\n\u003ctd\u003e8mm (0.31in)\u003c\/td\u003e\n\u003ctd\u003e13mm (0.51in)\u003c\/td\u003e\n\u003ctd\u003e5.3mm (0.21in)\u003c\/td\u003e\n\u003ctd\u003e18mm (0.71in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e40mm (1.57in)\u003c\/td\u003e\n\u003ctd\u003e8mm (0.31in)\u003c\/td\u003e\n\u003ctd\u003e13mm (0.51in)\u003c\/td\u003e\n\u003ctd\u003e5.3mm (0.21in)\u003c\/td\u003e\n\u003ctd\u003e24mm (0.94in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e60mm (2.36in)\u003c\/td\u003e\n\u003ctd\u003e8mm (0.31in)\u003c\/td\u003e\n\u003ctd\u003e13mm (0.51in)\u003c\/td\u003e\n\u003ctd\u003e5.3mm (0.21in)\u003c\/td\u003e\n\u003ctd\u003e36mm (1.42in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e80mm (3.15in)\u003c\/td\u003e\n\u003ctd\u003e8mm (0.31in)\u003c\/td\u003e\n\u003ctd\u003e13mm (0.51in)\u003c\/td\u003e\n\u003ctd\u003e5.3mm (0.21in)\u003c\/td\u003e\n\u003ctd\u003e48mm (1.89in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e100mm (3.94in)\u003c\/td\u003e\n\u003ctd\u003e8mm (0.31in)\u003c\/td\u003e\n\u003ctd\u003e13mm (0.51in)\u003c\/td\u003e\n\u003ctd\u003e5.3mm (0.21in)\u003c\/td\u003e\n\u003ctd\u003e60mm (2.36in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e140mm (5.51in)\u003c\/td\u003e\n\u003ctd\u003e8mm (0.31in)\u003c\/td\u003e\n\u003ctd\u003e13mm (0.51in)\u003c\/td\u003e\n\u003ctd\u003e5.3mm (0.21in)\u003c\/td\u003e\n\u003ctd\u003e84mm (3.31in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e160mm (6.30in)\u003c\/td\u003e\n\u003ctd\u003e8mm (0.31in)\u003c\/td\u003e\n\u003ctd\u003e13mm (0.51in)\u003c\/td\u003e\n\u003ctd\u003e5.3mm (0.21in)\u003c\/td\u003e\n\u003ctd\u003e96mm (3.78in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003eThread, head and drive dimensions are as specified in DIN 571 for the M8 (8mm) thread size.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eTypical Applications\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe combination of a coarse, deep wood-screw thread, high pull-out resistance and a spanner-drivable hexagon head makes these coach screws well suited to a wide range of structural and semi-structural timber fixing tasks, including:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eDecking frames, ledger boards and joists, where high pull-out resistance and spanner-driven torque suit structural timber-to-timber connections.\u003c\/li\u003e\n\u003cli\u003eFence posts, rails and gate hardware, including heavier gate fittings that need a secure, split-resistant fixing.\u003c\/li\u003e\n\u003cli\u003eGeneral timber framing and carpentry work, wherever a coarse-thread, hex-drive fastener is preferred over a standard wood screw.\u003c\/li\u003e\n\u003cli\u003eFurniture making, interior fittings, and repair and renovation projects in timber.\u003c\/li\u003e\n\u003cli\u003eLandscaping projects such as railway-sleeper retaining walls and raised beds, where the longer lengths bite deep into thick timber sections.\u003c\/li\u003e\n\u003cli\u003eWith a wall plug, fixing heavy-duty ironmongery, brackets and fittings into brick, block or concrete.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eInstallation Guidance\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003ePre-drilling correctly is the single biggest factor in a strong, split-free fixing with a coach screw this size. As a general guide:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003ePre-drill a pilot hole – strongly recommended to prevent the timber splitting and to ease driving.\u003c\/li\u003e\n\u003cli\u003eDrill a clearance hole through the first (fixing) timber, sized to the screw's shank.\u003c\/li\u003e\n\u003cli\u003eDrill a smaller pilot hole into the second timber, sized to roughly the thread's root diameter – use a smaller pilot in softer timbers than in dense hardwoods.\u003c\/li\u003e\n\u003cli\u003eDrill to at least the full length of the screw before driving.\u003c\/li\u003e\n\u003cli\u003eDrive home with a 13mm (0.51in) spanner or socket.\u003c\/li\u003e\n\u003cli\u003eFit a washer under the head – good practice that spreads the load and stops the head sinking into softer timber.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eCommon Questions\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhich length do I need?\u003c\/strong\u003e\u003cbr\u003eChoose a length that passes through the timber you are fixing and leaves the threaded part in the timber beneath. Thread length is 60% of the screw length, listed for every size in the table above.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat spanner or socket fits?\u003c\/strong\u003e\u003cbr\u003eA 13mm (0.51in) spanner or socket on every length.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDo I need to pre-drill?\u003c\/strong\u003e\u003cbr\u003eYes, a pilot hole is strongly recommended to prevent splitting: a clearance hole through the first timber and a smaller pilot hole into the second, as in the Installation Guidance above.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I fix them into brick or concrete?\u003c\/strong\u003e\u003cbr\u003eYes, with a suitable wall plug in brick, block or concrete.\u003c\/p\u003e","brand":"DIYUK","offers":[{"title":"30mm \/ 1","offer_id":53538263073149,"sku":"DIN571-M8x30-01","price":5.47,"currency_code":"GBP","in_stock":true},{"title":"30mm \/ 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