{"product_id":"black-hex-socket-countersunk-bolts-din-7991","title":"DIYUK Black Oxide Hex Socket Countersunk Bolts, DIN 7991 Grade 10.9 Carbon Steel, Allen Key Flat Head Screws, M4x8mm to M8x35mm","description":"\u003cp\u003e\u003cstrong\u003eCountersunk hex socket bolts manufactured to DIN 7991\u003c\/strong\u003e, made from carbon steel to property class 10.9.\u003c\/p\u003e\n\u003cp\u003eThe defining feature is the head geometry: a conical 90° countersunk profile that seats flush with, or just below, the surrounding material once fully driven home, leaving a smooth, snag-free surface rather than a proud bolt head. Drive is via a fully recessed internal hexagon (Allen key) socket, so you can tighten the bolt with an Allen key, straight down the centre of the fastener – useful both for reaching full seating on a hard carbon-steel bolt and for working in a recess too shallow or tight for a spanner or screwdriver. The bolts have a black oxide finish and are fully threaded in every size.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eKey Features\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eManufactured to DIN 7991\u003c\/li\u003e\n\u003cli\u003eProperty class 10.9 carbon steel\u003c\/li\u003e\n\u003cli\u003e90° conical countersunk head sits flush with, or below, the surrounding surface for a smooth, snag-free finish\u003c\/li\u003e\n\u003cli\u003eFully recessed internal hexagon (Allen key) drive lets you tighten the bolt straight down the centre of the fastener, even in tight or recessed fixing points\u003c\/li\u003e\n\u003cli\u003eBlack oxide finish\u003c\/li\u003e\n\u003cli\u003eTen sizes covering M4 x 8mm up to M8 x 35mm, fully threaded, in packs of 2, 10, 50 or 100\u003c\/li\u003e\n\u003cli\u003ePairs with a tapped hole, standard nut, or threaded insert of the matching metric thread\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\u003eSize\u003c\/th\u003e\n\u003cth\u003eHead diameter\u003c\/th\u003e\n\u003cth\u003eHead height\u003c\/th\u003e\n\u003cth\u003eHex socket (Allen key) size\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eM4 x 8mm (0.31in)\u003c\/td\u003e\n\u003ctd\u003e8mm (0.31in)\u003c\/td\u003e\n\u003ctd\u003e2.3mm (0.09in)\u003c\/td\u003e\n\u003ctd\u003e2.5mm (0.10in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM4 x 12mm (0.47in)\u003c\/td\u003e\n\u003ctd\u003e8mm (0.31in)\u003c\/td\u003e\n\u003ctd\u003e2.3mm (0.09in)\u003c\/td\u003e\n\u003ctd\u003e2.5mm (0.10in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM5 x 10mm (0.39in)\u003c\/td\u003e\n\u003ctd\u003e10mm (0.39in)\u003c\/td\u003e\n\u003ctd\u003e2.8mm (0.11in)\u003c\/td\u003e\n\u003ctd\u003e3mm (0.12in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM5 x 20mm (0.79in)\u003c\/td\u003e\n\u003ctd\u003e10mm (0.39in)\u003c\/td\u003e\n\u003ctd\u003e2.8mm (0.11in)\u003c\/td\u003e\n\u003ctd\u003e3mm (0.12in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM6 x 16mm (0.63in)\u003c\/td\u003e\n\u003ctd\u003e12mm (0.47in)\u003c\/td\u003e\n\u003ctd\u003e3.3mm (0.13in)\u003c\/td\u003e\n\u003ctd\u003e4mm (0.16in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM6 x 30mm (1.18in)\u003c\/td\u003e\n\u003ctd\u003e12mm (0.47in)\u003c\/td\u003e\n\u003ctd\u003e3.3mm (0.13in)\u003c\/td\u003e\n\u003ctd\u003e4mm (0.16in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM8 x 20mm (0.79in)\u003c\/td\u003e\n\u003ctd\u003e16mm (0.63in)\u003c\/td\u003e\n\u003ctd\u003e4.4mm (0.17in)\u003c\/td\u003e\n\u003ctd\u003e5mm (0.20in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM8 x 25mm (0.98in)\u003c\/td\u003e\n\u003ctd\u003e16mm (0.63in)\u003c\/td\u003e\n\u003ctd\u003e4.4mm (0.17in)\u003c\/td\u003e\n\u003ctd\u003e5mm (0.20in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM8 x 30mm (1.18in)\u003c\/td\u003e\n\u003ctd\u003e16mm (0.63in)\u003c\/td\u003e\n\u003ctd\u003e4.4mm (0.17in)\u003c\/td\u003e\n\u003ctd\u003e5mm (0.20in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM8 x 35mm (1.38in)\u003c\/td\u003e\n\u003ctd\u003e16mm (0.63in)\u003c\/td\u003e\n\u003ctd\u003e4.4mm (0.17in)\u003c\/td\u003e\n\u003ctd\u003e5mm (0.20in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cstrong\u003eSizing note:\u003c\/strong\u003e unlike dome or cap head screws, countersunk bolts are measured by their \u003cem\u003etotal\u003c\/em\u003e length, including the head – measure from the flat top face of the head to the tip of the thread to confirm the correct length for your application.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eChoosing the Size\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe Allen recess allows convenient screwing and tightening with an Allen wrench, so installation needs only standard tools. Each diameter takes a hex key of its own size: 2.5mm (0.10in) for M4, 3mm (0.12in) for M5, 4mm (0.16in) for M6, and 5mm (0.20in) for M8, as listed in the specification table above. The bolt pairs with a tapped hole, a standard nut, or a threaded insert of the matching metric thread on the far side of the joint.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eTypical Applications\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eFlat-pack furniture and cabinetry assembly, where a flush head avoids snagging on clothing, hands, or adjoining panels\u003c\/li\u003e\n\u003cli\u003e3D printer and machine frame builds, where a compact, fully recessed drive suits enclosed or awkward-to-reach fixing points\u003c\/li\u003e\n\u003cli\u003eElectronics enclosures, where a smooth external profile matters for both appearance and safe handling\u003c\/li\u003e\n\u003cli\u003eGeneral workshop and DIY fixing jobs needing a high-tensile, low-profile bolt that can be driven with a simple Allen key rather than a spanner\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eCommon Questions\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat sizes are available?\u003c\/strong\u003e\u003cbr\u003eTen sizes (thread diameter x total length): M4 x 8mm, M4 x 12mm, M5 x 10mm, M5 x 20mm, M6 x 16mm, M6 x 30mm, M8 x 20mm, M8 x 25mm, M8 x 30mm and M8 x 35mm.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat pack sizes are available?\u003c\/strong\u003e\u003cbr\u003ePacks of 2, 10, 50 or 100 in every size.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat size Allen key do I need?\u003c\/strong\u003e\u003cbr\u003e2.5mm for M4, 3mm for M5, 4mm for M6 and 5mm for M8 (0.10in, 0.12in, 0.16in and 0.20in).\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow are countersunk bolts measured?\u003c\/strong\u003e\u003cbr\u003eBy total length, from the flat top face of the head to the tip of the thread; an M8 x 35mm countersunk socket bolt is 35mm long overall.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eAre these bolts fully threaded?\u003c\/strong\u003e\u003cbr\u003eYes, every size is threaded along its full length.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat are they made of?\u003c\/strong\u003e\u003cbr\u003eCarbon steel, property class 10.9 (often listed as grade 10.9), with a black oxide finish, manufactured to DIN 7991.\u003c\/p\u003e","brand":"DIYUK","offers":[{"title":"M4 x 8mm \/ 2","offer_id":57459156517245,"sku":"DIN7991-BLACK-M4x08-2","price":5.47,"currency_code":"GBP","in_stock":false},{"title":"M4 x 8mm \/ 10","offer_id":57459156550013,"sku":"DIN7991-BLACK-M4x08-10","price":5.85,"currency_code":"GBP","in_stock":false},{"title":"M4 x 8mm \/ 50","offer_id":57459156582781,"sku":"DIN7991-BLACK-M4x08-50","price":6.23,"currency_code":"GBP","in_stock":false},{"title":"M4 x 8mm \/ 100","offer_id":57459156615549,"sku":"DIN7991-BLACK-M4x08-100","price":7.48,"currency_code":"GBP","in_stock":false},{"title":"M4 x 12mm \/ 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