{"product_id":"osg-1768701-spiral-flute-extension-tap-3-8-16-unc","title":"Osg 1768701 Spiral Flute Extension Tap 3\/8-16 Unc","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\u003cp\u003eThe OSG 1768701 is a spiral flute extension tap designed for threading 3\/8-16 UNC internal threads in applications where standard-length taps cannot reach. Built from vanadium high-speed steel with a steam oxide finish, this tap delivers controlled chip ejection through its 30-degree right-hand helix and three-flute geometry. The modified bottoming chamfer allows threading closer to the bottom of blind holes than a standard plug or taper chamfer. At 6 inches overall length with a 1.875-inch neck, it provides the reach needed for recessed or deep-pocket threading operations. Shank diameter is 0.381 inches with a reduced shank design and a 0.286-inch square drive. It produces 3B class of fit threads.\u003c\/p\u003e\u003cp\u003eThis tap is suited for production and maintenance threading on carbon steel, hardened steel, and stainless steel workpieces. The extended neck length makes it practical for fixture work, deep counterbores, or any setup where the tap must pass through a bushing or guide before reaching the threaded bore. It is commonly used by machinists and tool-and-die technicians running CNC or manual tapping operations. The steam oxide coating reduces friction and provides moderate lubrication retention during cutting.\u003c\/p\u003e\u003ch4\u003eKey Features\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003eSpiral flute geometry ejects chips back out of blind holes for cleaner threading\u003c\/li\u003e\n\u003cli\u003e30-degree right-hand helix angle suits a wide range of threading applications\u003c\/li\u003e\n\u003cli\u003eModified bottoming chamfer threads closer to the bottom of blind bores\u003c\/li\u003e\n\u003cli\u003eVanadium high-speed steel construction handles carbon steel, hardened steel, and stainless steel\u003c\/li\u003e\n\u003cli\u003eSteam oxide finish reduces friction and improves lubrication retention\u003c\/li\u003e\n\u003cli\u003eReduced shank with 6-inch OAL and 1.875-inch neck for extended reach\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eCompatibility\u003c\/h4\u003e\u003cp\u003eDesigned for threading 3\/8-16 UNC right-hand internal threads to a 3B class of fit in carbon steel, hardened steel, and stainless steel workpieces. Part of OSG Series 398.\u003c\/p\u003e\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\u003cp\u003eInstallation and use should be performed by a qualified machinist or toolmaker familiar with tapping speeds, feeds, and cutting fluid requirements for the workpiece material. Secure the tap in an appropriate tap driver or CNC spindle rated for the square drive size before operation. Ensure the work-holding fixture and guide bushings are aligned to avoid tap breakage, particularly given the reduced shank and extended neck geometry. Never force a tap that has stopped cutting — back it out and clear chips before continuing.\u003c\/p\u003e\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread Size\u003c\/strong\u003e: 3\/8-16\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread Standard\u003c\/strong\u003e: UNC\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNumber of Flutes\u003c\/strong\u003e: 3\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread Limit\u003c\/strong\u003e: H3\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eClass of Fit\u003c\/strong\u003e: 3B\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTap Type\u003c\/strong\u003e: Spiral Flute\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eChamfer\u003c\/strong\u003e: Modified Bottoming\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread Direction\u003c\/strong\u003e: Right Hand\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlute Direction\u003c\/strong\u003e: Right Hand\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHelix Angle\u003c\/strong\u003e: 30 degrees\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOverall Length\u003c\/strong\u003e: 6 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread Length\u003c\/strong\u003e: 0.5 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNeck Length\u003c\/strong\u003e: 1.875 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eShank Diameter\u003c\/strong\u003e: 0.381 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSquare Size\u003c\/strong\u003e: 0.286 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSquare Length\u003c\/strong\u003e: 0.4375 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReduced Shank\u003c\/strong\u003e: Yes\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial\u003c\/strong\u003e: Vanadium High-Speed Steel\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCoating\/Finish\u003c\/strong\u003e: Steam Oxide\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial Application\u003c\/strong\u003e: Carbon Steel, Hardened Steel, Stainless Steel\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSeries\u003c\/strong\u003e: 398\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 0.168 pounds\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eStandard Information\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand\u003c\/strong\u003e: OSG\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: 1768701\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"OSG","offers":[{"title":"Default Title","offer_id":51744629555506,"sku":"1768701","price":112.73,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/f460ed950d1b51aa50b4433d7e102581.jpg?v=1788859209","url":"https:\/\/voomisupply.com\/products\/osg-1768701-spiral-flute-extension-tap-3-8-16-unc","provider":"Voomi Supply","version":"1.0","type":"link"}