{"product_id":"osg-3147303-straight-flute-tap-1-4-20-unc-bottoming","title":"Osg 3147303 Straight Flute Tap 1\/4-20 Unc Bottoming","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\u003cp\u003eThe OSG 3147303 is a straight flute bottoming tap designed for cutting internal threads in blind and through holes requiring full thread depth close to the bottom. Manufactured from cobalt high-speed steel with a nitride coating, it is built for durability and wear resistance in production tapping applications. The tap cuts a 1\/4-20 UNC right-hand thread with a bottoming chamfer, meaning it has minimal lead-in and can thread nearly to the base of a blind hole. With 4 flutes and an H7 thread limit, it holds tight tolerances suitable for precision assemblies. Machinists and tool-and-die professionals install this tap in drill presses, CNC machining centers, and tapping arms.\u003c\/p\u003e\u003cp\u003eThe OSG 3147303 is suited for tapping plastic materials and similar low-resistance workpieces. Its bottoming chamfer makes it the correct choice when the full thread must extend as deep as possible into a blind hole, often used as the finishing tap in a two-tap or three-tap sequence following a spiral point or plug tap. The cobalt construction handles moderate heat buildup during dry or minimal-lubrication tapping cycles. This tap fits standard 1\/4-inch tap holders and collets used in manual and CNC setups.\u003c\/p\u003e\u003ch4\u003eKey Features\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003eBottoming chamfer for threading close to the bottom of blind holes\u003c\/li\u003e\n\u003cli\u003eCobalt high-speed steel construction for extended wear life\u003c\/li\u003e\n\u003cli\u003eNitride coating reduces friction and improves tool longevity\u003c\/li\u003e\n\u003cli\u003eH7 thread limit for controlled tolerance in precision fits\u003c\/li\u003e\n\u003cli\u003e4 straight flutes suited for short-chip materials such as plastic\u003c\/li\u003e\n\u003cli\u003eRight-hand thread, no coolant-through requirement\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eCompatibility\u003c\/h4\u003e\u003cp\u003eDesigned as an OEM-style replacement tap for standard 1\/4-20 UNC threading operations in compatible tap holders and collets accepting a 0.255-inch shank diameter.\u003c\/p\u003e\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\u003cp\u003eInstall this tap in a properly sized tap holder or collet matched to the 0.255-inch shank diameter. Ensure the workpiece is securely fixtured and the pilot hole is drilled to the correct tap drill size for 1\/4-20 UNC before tapping. Apply appropriate cutting fluid or follow the machine tool manufacturer's lubrication guidance for the workpiece material. Inspect tap condition regularly and replace when cutting torque increases noticeably or thread quality degrades.\u003c\/p\u003e\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread Size\u003c\/strong\u003e: 1\/4-20 UNC\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread Standard\u003c\/strong\u003e: UNC\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThreads per Inch\u003c\/strong\u003e: 20\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eChamfer Type\u003c\/strong\u003e: Bottoming\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNumber of Flutes\u003c\/strong\u003e: 4\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread Direction\u003c\/strong\u003e: Right Hand\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread Limit\u003c\/strong\u003e: H7\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOverall Length\u003c\/strong\u003e: 2.5 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread Length\u003c\/strong\u003e: 0.594 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eShank Diameter\u003c\/strong\u003e: 0.255 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSquare Length\u003c\/strong\u003e: 0.3125 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSquare Size\u003c\/strong\u003e: 0.191 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNeck Length\u003c\/strong\u003e: 0.9966 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial\u003c\/strong\u003e: Cobalt High-Speed Steel\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCoating\/Finish\u003c\/strong\u003e: Nitride\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial Application\u003c\/strong\u003e: Plastic\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCoolant Through\u003c\/strong\u003e: No\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSeries\u003c\/strong\u003e: 114\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 0.03 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: 3147303\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"OSG","offers":[{"title":"Default Title","offer_id":51732569129266,"sku":"3147303","price":23.46,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/9677a863ddb31cc8a05f7baffeea6078.jpg?v=1788744534","url":"https:\/\/voomisupply.com\/products\/osg-3147303-straight-flute-tap-1-4-20-unc-bottoming","provider":"Voomi Supply","version":"1.0","type":"link"}