{"product_id":"osg-1703601-spiral-flute-tap-1-4-28-unf-modified-bottoming","title":"Osg 1703601 Spiral Flute Tap 1\/4-28 Unf Modified Bottoming","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe OSG 1703601 is a spiral flute tap designed for cutting internal 1\/4-28 UNF right-hand threads in a range of demanding materials. Built from powdered metal with a steam oxide coating, it offers improved lubricity and corrosion resistance compared to standard HSS taps. The modified bottoming chamfer allows threading close to the bottom of blind holes. With a 15-degree helix angle and 3 right-hand spiral flutes, the tool efficiently evacuates chips upward out of the hole during tapping operations. Machinists, toolroom technicians, and maintenance professionals working on precision assemblies install this tap in CNC machining centers, drill presses, and tapping arms.\u003c\/p\u003e\n\u003cp\u003eThis tap is suited for threading alloy steel, stainless steel, hardened steel, titanium, and high-nickel alloys where standard carbon steel or HSS tooling falls short. The spiral flute design makes it particularly effective in blind-hole applications where chip buildup can cause tap breakage or thread damage. Thread limit H4 and Class of Fit 2B ensure threads produced meet standard tolerance requirements for general fastener applications in manufacturing and repair environments.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e1\/4-28 UNF thread form with right-hand thread direction\u003c\/li\u003e\n  \u003cli\u003eModified bottoming chamfer for threading close to blind hole floors\u003c\/li\u003e\n  \u003cli\u003e3 right-hand spiral flutes with 15-degree helix angle for upward chip evacuation\u003c\/li\u003e\n  \u003cli\u003ePowdered metal construction for extended tool life in tough materials\u003c\/li\u003e\n  \u003cli\u003eSteam oxide coating reduces friction and provides mild corrosion resistance\u003c\/li\u003e\n  \u003cli\u003eH4 thread limit, Class of Fit 2B for standard fastener tolerance applications\u003c\/li\u003e\n  \u003cli\u003eNo coolant-through requirement — compatible with standard flood or manual lubrication\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eRated for use in alloy steel, stainless steel, hardened steel, titanium, and high-nickel alloys. Part of OSG Series 313.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eInstall in a tap holder, tapping chuck, or rigid tapping setup appropriate for 1\/4-28 UNF tooling. Always apply a suitable cutting fluid or tapping compound for the workpiece material — this is especially important with stainless steel, titanium, and high-nickel alloys. Ensure the tap is properly aligned with the pilot hole before engagement to avoid cross-threading or tool breakage. Follow shop-standard speeds and feeds for the workpiece material and consult OSG Series 313 documentation for recommended parameters.\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\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThread Standard\u003c\/strong\u003e: 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\u003eFlute Style\u003c\/strong\u003e: Spiral\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: 15 degrees\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThread Direction\u003c\/strong\u003e: Right Hand\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eChamfer\u003c\/strong\u003e: Modified Bottoming\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eClass of Fit\u003c\/strong\u003e: 2B\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThread Limit\u003c\/strong\u003e: H4\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: Steam Oxide\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: 0.398 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\u003eNeck Length\u003c\/strong\u003e: 0.996 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\u003eCoolant Through\u003c\/strong\u003e: No\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSeries\u003c\/strong\u003e: 313\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 0.035 pounds\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: 1703601\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"OSG","offers":[{"title":"Default Title","offer_id":51732371570994,"sku":"1703601","price":56.4,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/2a919ca79e01f031cd8f7f813828b12f_edadc4c5-32fe-4eb3-9c47-e03a2305338a.jpg?v=1788742178","url":"https:\/\/voomisupply.com\/products\/osg-1703601-spiral-flute-tap-1-4-28-unf-modified-bottoming","provider":"Voomi Supply","version":"1.0","type":"link"}