{"product_id":"1639-cylinder-head-drills-extension","title":"FAMAG 1639 FORSTNER BIT EXTENSIONS","description":"\u003cp data-start=\"336\" data-end=\"787\"\u003eThe FAMAG 1639 Extensions let you transform standard cylinder boring bits and any tool with an 8 – 13 mm shank into deep-hole drilling powerhouses. Crafted from hardened tool steel with precision-ground run-out, each rod secures your bit via four 120°-spaced clamp screws and three machined flats for perfect concentricity. \u003c\/p\u003e\n\u003cp data-start=\"336\" data-end=\"787\"\u003e\u003cstrong\u003e\u003cspan style=\"color: #ff2a00;\"\u003eInner Diameter (ID) 8mm are suitable for Bormax forstners sizes from 8mm - 21mm (Including Imperial Equivelant) \u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp data-start=\"336\" data-end=\"787\"\u003e\u003cstrong\u003e\u003cspan style=\"color: #ff2a00;\"\u003eInner Diameter (ID) 10mm are suitable for Bormax forstners from 22mm - 46mm (Including Imperial Equivelant) \u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp data-start=\"336\" data-end=\"787\"\u003e\u003cstrong\u003e\u003cspan style=\"color: #ff2a00;\"\u003eInner Diameter (ID) 13mm are suitable for Bormax forstners  sizes from 47mm - 85mm (Including Imperial Equivelant) \u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003ch4 data-start=\"789\" data-end=\"822\"\u003e📏 Technical Specifications\u003c\/h4\u003e\n\u003cul data-start=\"823\" data-end=\"1282\"\u003e\n\u003cli data-start=\"823\" data-end=\"896\"\u003e\n\u003cp data-start=\"825\" data-end=\"896\"\u003e\u003cstrong data-start=\"825\" data-end=\"849\"\u003eInner Diameter (ID):\u003c\/strong\u003e 8 mm, 10 mm, 12 mm or 13 mm (model-specific)\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"897\" data-end=\"966\"\u003e\n\u003cp data-start=\"899\" data-end=\"966\"\u003e\u003cstrong data-start=\"899\" data-end=\"924\"\u003eOverall Lengths (GL):\u003c\/strong\u003e 80 mm, 125 mm, 250 mm (three-piece set)\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"967\" data-end=\"1039\"\u003e\n\u003cp data-start=\"969\" data-end=\"1039\"\u003e\u003cstrong data-start=\"969\" data-end=\"992\"\u003eUsable Length (NL):\u003c\/strong\u003e GL minus clamp-block height (~NL = GL–40 mm)\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"1040\" data-end=\"1106\"\u003e\n\u003cp data-start=\"1042\" data-end=\"1106\"\u003e\u003cstrong data-start=\"1042\" data-end=\"1059\"\u003eClamp System:\u003c\/strong\u003e Four hardened-steel screws at 120° intervals\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"1107\" data-end=\"1171\"\u003e\n\u003cp data-start=\"1109\" data-end=\"1171\"\u003e\u003cstrong data-start=\"1109\" data-end=\"1125\"\u003eShaft Flats:\u003c\/strong\u003e Three milled surfaces for zero-slip run-out\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"1172\" data-end=\"1230\"\u003e\n\u003cp data-start=\"1174\" data-end=\"1230\"\u003e\u003cstrong data-start=\"1174\" data-end=\"1187\"\u003eMaterial:\u003c\/strong\u003e Hardened, corrosion-resistant tool steel\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4 data-start=\"1284\" data-end=\"1305\"\u003e🎯 Key Benefits\u003c\/h4\u003e\n\u003cul data-start=\"1306\" data-end=\"1823\"\u003e\n\u003cli data-start=\"1306\" data-end=\"1415\"\u003e\n\u003cp data-start=\"1308\" data-end=\"1415\"\u003e\u003cstrong data-start=\"1308\" data-end=\"1327\"\u003eExtended Reach:\u003c\/strong\u003e Drill beyond standard bit length for deep mortises, dowel holes, and lathe hollowing.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"1416\" data-end=\"1524\"\u003e\n\u003cp data-start=\"1418\" data-end=\"1524\"\u003e\u003cstrong data-start=\"1418\" data-end=\"1442\"\u003ePrecision Alignment:\u003c\/strong\u003e Clamp screws and shaft flats eliminate wobble, ensuring clean, tear-free holes.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"1525\" data-end=\"1636\"\u003e\n\u003cp data-start=\"1527\" data-end=\"1636\"\u003e\u003cstrong data-start=\"1527\" data-end=\"1555\"\u003eVersatile Compatibility:\u003c\/strong\u003e Works with all cylinder boring bits and accessories sporting an 8–13 mm shank.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"1637\" data-end=\"1736\"\u003e\n\u003cp data-start=\"1639\" data-end=\"1736\"\u003e\u003cstrong data-start=\"1639\" data-end=\"1664\"\u003eDurable Construction:\u003c\/strong\u003e Hardened tool steel resists bending and wear, even under heavy loads.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4 data-start=\"1825\" data-end=\"1850\"\u003e⚙️ Application Tips\u003c\/h4\u003e\n\u003col data-start=\"1851\" data-end=\"2353\"\u003e\n\u003cli data-start=\"1851\" data-end=\"1944\"\u003e\n\u003cp data-start=\"1854\" data-end=\"1944\"\u003e\u003cstrong data-start=\"1854\" data-end=\"1887\"\u003eSelect the Correct Extension:\u003c\/strong\u003e Match ID to your bit’s shank diameter before mounting.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"1945\" data-end=\"2051\"\u003e\n\u003cp data-start=\"1948\" data-end=\"2051\"\u003e\u003cstrong data-start=\"1948\" data-end=\"1967\"\u003eSecure the Bit:\u003c\/strong\u003e Insert the bit fully, then tighten all four clamp screws in alternating sequence.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2052\" data-end=\"2154\"\u003e\n\u003cp data-start=\"2055\" data-end=\"2154\"\u003e\u003cstrong data-start=\"2055\" data-end=\"2080\"\u003eBalance Speed \u0026amp; Feed:\u003c\/strong\u003e Reduce RPM slightly when using longer extensions to maintain stability.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2155\" data-end=\"2257\"\u003e\n\u003cp data-start=\"2158\" data-end=\"2257\"\u003e\u003cstrong data-start=\"2158\" data-end=\"2184\"\u003eClear Chips Regularly:\u003c\/strong\u003e Periodically retract and clear swarf to prevent binding in deep holes.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2258\" data-end=\"2353\"\u003e\n\u003cp data-start=\"2261\" data-end=\"2353\"\u003e\u003cstrong data-start=\"2261\" data-end=\"2284\"\u003eInspect \u0026amp; Maintain:\u003c\/strong\u003e Check run-out on a dial gauge and re-tighten screws before each use.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ol\u003e","brand":"Famag Tools","offers":[{"title":"8mm \/ 80mm","offer_id":51583415517523,"sku":"F1639011","price":28.91,"currency_code":"GBP","in_stock":true},{"title":"8mm \/ 125mm","offer_id":51583501271379,"sku":"F1639003","price":32.34,"currency_code":"GBP","in_stock":true},{"title":"8mm \/ 250mm","offer_id":51583501304147,"sku":"F1639004","price":35.77,"currency_code":"GBP","in_stock":true},{"title":"10mm \/ 80mm","offer_id":51583501369683,"sku":"F1639010","price":28.91,"currency_code":"GBP","in_stock":true},{"title":"10mm \/ 125mm","offer_id":51583501402451,"sku":"F1639001","price":32.34,"currency_code":"GBP","in_stock":true},{"title":"10mm \/ 250mm","offer_id":51583501435219,"sku":"F1639002","price":35.77,"currency_code":"GBP","in_stock":true},{"title":"10mm \/ 400mm","offer_id":51583501467987,"sku":"F1639009","price":60.91,"currency_code":"GBP","in_stock":true},{"title":"12mm \/ 400mm","offer_id":51583501599059,"sku":"F1639007","price":58.49,"currency_code":"GBP","in_stock":true},{"title":"13mm \/ 125mm","offer_id":51583501664595,"sku":"F1639005","price":35.77,"currency_code":"GBP","in_stock":true},{"title":"13mm \/ 250mm","offer_id":51583501697363,"sku":"F1639006","price":40.55,"currency_code":"GBP","in_stock":true},{"title":"13mm \/ 400mm","offer_id":51583501730131,"sku":"F1639008","price":58.49,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0938\/4843\/7075\/files\/Famag-F1639001-cylinder-head-extension-_10mm.jpg?v=1758807499","url":"https:\/\/wooddrills.co.uk\/products\/1639-cylinder-head-drills-extension","provider":"Wooddrills.co.uk","version":"1.0","type":"link"}