{"product_id":"osg-31520608-spiral-flute-sti-tap-1-4-28-unf-h3","title":"Osg 31520608 Spiral Flute Sti Tap 1\/4-28 Unf H3","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe OSG 31520608 is a spiral flute STI (Screw Thread Insert) tap designed for cutting 1\/4-28 UNF internal threads in applications that require a helical coil insert to be installed afterward. The spiral flute geometry pulls chips up and out of the hole during the tapping operation, making it well suited for blind-hole work where chip evacuation is critical. Built from powdered metal with a V-series coating, this tap delivers consistent tool life in a range of ferrous and non-ferrous materials. The H3 thread limit provides proper tolerance for STI threading operations where insert fit is essential.\u003c\/p\u003e\n\u003cp\u003eThis tap is used in maintenance, repair, and manufacturing environments where stripped or worn threads are being restored using helical coil inserts, or where STI threads are being cut in new components. Typical applications include aerospace, automotive, and industrial equipment repair. It is installed by machinists and tool-and-die professionals using a standard tap handle or machine tapping setup. The right-hand flute direction and 10-degree helix angle are suited for general-purpose machine or hand tapping.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003eSpiral flute design promotes upward chip evacuation, ideal for blind-hole tapping\u003c\/li\u003e\n  \u003cli\u003eSTI thread form cuts oversized threads sized to accept helical coil inserts\u003c\/li\u003e\n  \u003cli\u003eH3 thread limit ensures proper tolerance for insert installation\u003c\/li\u003e\n  \u003cli\u003ePowdered metal construction provides improved wear resistance over standard HSS\u003c\/li\u003e\n  \u003cli\u003eV-series coating reduces friction and extends tool life\u003c\/li\u003e\n  \u003cli\u003e3-flute configuration balances chip clearance and cutting stability\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eDesigned as an OEM-style STI tap for use with 1\/4-28 UNF helical coil thread insert systems in blind or through-hole applications.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eThis tap should be installed and operated by qualified machinists or maintenance technicians familiar with STI tapping procedures. Ensure the workpiece is secured and the spindle or tap handle is properly aligned before beginning the cut. Use appropriate cutting fluid for the material being tapped to extend tool life and improve thread quality. Follow the insert manufacturer's guidelines for tap drill size and insert installation after tapping is complete.\u003c\/p\u003e\n\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThread Size\u003c\/strong\u003e: 1\/4-28 UNF\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThread Standard\u003c\/strong\u003e: UNF\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThread Limit\u003c\/strong\u003e: H3\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNumber of Flutes\u003c\/strong\u003e: 3\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: 10 degrees\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThread Length\u003c\/strong\u003e: 0.5 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThreads per Inch\u003c\/strong\u003e: 28\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaterial\u003c\/strong\u003e: Powdered Metal\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCoating\/Finish\u003c\/strong\u003e: V\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSeries\u003c\/strong\u003e: 315Ni\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 0.052 pounds\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eUNSPSC Code\u003c\/strong\u003e: 27112806\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eStandard Information\u003c\/h4\u003e\n\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: 31520608\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"OSG","offers":[{"title":"Default Title","offer_id":51746210971954,"sku":"31520608","price":98.04,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/926ffe43c32955ee6d40515f6ab54219.jpg?v=1788867169","url":"https:\/\/voomisupply.com\/products\/osg-31520608-spiral-flute-sti-tap-1-4-28-unf-h3","provider":"Voomi Supply","version":"1.0","type":"link"}