{"product_id":"emuge-bu513710-5639-spiral-point-sti-tap-1-4-28-unf","title":"Emuge BU513710.5639 Spiral Point Sti Tap 1\/4-28 Unf","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe EMUGE BU513710.5639 is a spiral point STI tap designed for threading 1\/4-28 UNF inserts into blind holes. Built from cobalt high-speed steel with a Titanium Nitride (TiN) coating, it delivers extended tool life in demanding materials including stainless steel and carbon steel. The tap features a bottoming chamfer for threading close to the bottom of a blind hole, 3 flutes, an H2 thread limit, and a 3B class of fit. Overall length is 3.543 inches with a thread length of 0.3571 inches. It is intended for use by machinists, maintenance technicians, and trade professionals performing precision threaded insert installations.\u003c\/p\u003e\n\u003cp\u003eThis tap is used in applications where a STI (Screw Thread Insert) is required to restore or create a standard 1\/4-28 UNF thread in a blind hole. Typical install scenarios include repair work on stripped threads in steel or stainless steel components, as well as new production threading operations where insert-style thread reinforcement is specified. The bottoming chamfer style allows full thread engagement depth even in shallow blind holes, making it well suited for tight-tolerance mechanical assemblies in industrial, aerospace-adjacent maintenance, and heavy equipment service environments.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003eSTI thread form for use with 1\/4-28 UNF threaded inserts in blind holes\u003c\/li\u003e\n  \u003cli\u003eCobalt HSS construction provides heat and wear resistance in stainless steel and alloy steel\u003c\/li\u003e\n  \u003cli\u003eTitanium Nitride (TiN) coating reduces friction and extends cutting edge life\u003c\/li\u003e\n  \u003cli\u003eBottoming chamfer allows threading to near the base of a blind hole\u003c\/li\u003e\n  \u003cli\u003eH2 thread limit and 3B class of fit ensure consistent, controlled thread tolerances\u003c\/li\u003e\n  \u003cli\u003e3 flutes with spiral point geometry push chips forward during through and blind hole operations\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eDesigned for cutting 1\/4-28 UNF STI threads in stainless steel and steel workpieces. Intended for use with 1\/4-28 UNF threaded insert installation in blind hole applications per Series BU513710 specifications.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eThis tap should be installed and operated by qualified machinists or skilled maintenance technicians familiar with tapping speeds, cutting fluids, and thread insert procedures. Always secure the workpiece and use appropriate cutting fluid for the material being tapped, particularly when working with stainless steel. Ensure the tap is aligned perpendicular to the workpiece surface before beginning the cut to avoid thread damage or tap breakage. Follow machine shop safety practices and consult applicable tooling manufacturer guidance for recommended RPM and feed rates.\u003c\/p\u003e\n\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTap Size\u003c\/strong\u003e: 1\/4-28\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThread Standard\u003c\/strong\u003e: STI UNF\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThreads per Inch\u003c\/strong\u003e: 28\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNumber of Flutes\u003c\/strong\u003e: 3\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eChamfer Type\u003c\/strong\u003e: Bottoming\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eClass of Fit\u003c\/strong\u003e: 3B\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThread Limit\u003c\/strong\u003e: H2\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOverall Length\u003c\/strong\u003e: 3.543 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThread Length\u003c\/strong\u003e: 0.3571 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eShank Diameter\u003c\/strong\u003e: 0.318 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSquare Size\u003c\/strong\u003e: 0.318 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\u003c\/strong\u003e: Titanium Nitride (TiN)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eApplication\u003c\/strong\u003e: Blind Hole Threading\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaterial Application\u003c\/strong\u003e: Stainless Steel, Steel\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSeries\u003c\/strong\u003e: BU513710\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 0.0616 pounds\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eUNSPSC Code\u003c\/strong\u003e: 23241600\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: EMUGE\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: BU513710.5639\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"EMUGE","offers":[{"title":"Default Title","offer_id":52079658893618,"sku":"BU513710.5639","price":100.79,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/5f783c05950d7796f346dcf4b42c3436_2ce012b2-a499-4bd0-997a-d7c3b2f06cea.jpg?v=1790054985","url":"https:\/\/voomisupply.com\/products\/emuge-bu513710-5639-spiral-point-sti-tap-1-4-28-unf","provider":"Voomi Supply","version":"1.0","type":"link"}