{"product_id":"hertel-k008371as-spiral-flute-tap-1-4-28-unf-bottoming-hss","title":"Hertel K008371AS Spiral Flute Tap 1\/4-28 Unf Bottoming Hss","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe HERTEL K008371AS is a spiral flute tap designed for threading 1\/4-28 UNF holes in a bottoming configuration. Built from high-speed steel (HSS), it delivers consistent thread cutting in ferrous and non-ferrous metals where a full-depth thread is required close to the bottom of a blind hole. The tap features three right-hand flutes with a fast flute style and a 52-degree helix angle, which promotes efficient chip evacuation in short-chipping materials. The H3 thread limit and 3B class of fit make it suited for standard tolerance threaded assemblies. Overall length is 2.5 inches.\u003c\/p\u003e\n\u003cp\u003eThis tap is used in machine shops, manufacturing, and maintenance applications where 1\/4-28 UNF fine-thread fasteners are assembled into blind holes requiring maximum thread engagement. The bottoming chamfer — typically 1 to 2 threads of taper — allows threading nearly to the bottom of the hole after a plug or taper tap has started the thread. It is installed by machinists, tool-and-die technicians, and maintenance mechanics using a tapping head, CNC machine, or hand tap wrench. It does not support coolant-through delivery.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e1\/4-28 UNF thread form for fine-pitch applications requiring high tensile strength\u003c\/li\u003e\n  \u003cli\u003eBottoming chamfer for threading to the bottom of blind holes\u003c\/li\u003e\n  \u003cli\u003e52-degree helix angle with fast flute style for effective chip removal\u003c\/li\u003e\n  \u003cli\u003eH3 thread limit with 3B class of fit for standard tolerance assemblies\u003c\/li\u003e\n  \u003cli\u003eHigh-speed steel construction for durability across a range of workpiece materials\u003c\/li\u003e\n  \u003cli\u003eRight-hand thread and right-hand flute direction for conventional tapping operations\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eDesigned as a direct-use bottoming tap for 1\/4-28 UNF threaded blind holes in standard 3B tolerance applications. Verify pilot hole diameter per UNF tap drill charts before use.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eSecure the workpiece and ensure the pilot hole is drilled to the correct UNF tap drill diameter before beginning the threading operation. Use cutting fluid appropriate to the workpiece material to reduce heat and extend tap life. When using by hand, apply steady, even pressure and back off a partial turn periodically to break chips. Avoid forcing the tap against the bottom of the hole to prevent tap breakage.\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\u003eChamfer\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: 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 Style\u003c\/strong\u003e: Fast\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHelix Angle\u003c\/strong\u003e: 52 degrees\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\u003eOverall Length\u003c\/strong\u003e: 2.5 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaterial\u003c\/strong\u003e: High-Speed Steel\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCoolant Through\u003c\/strong\u003e: No\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 0.35 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: HERTEL\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: K008371AS\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"HERTEL","offers":[{"title":"Default Title","offer_id":51739111883058,"sku":"K008371AS","price":37.06,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/8d09bab6c849187a4d4a463bc1de6c45.jpg?v=1788809621","url":"https:\/\/voomisupply.com\/products\/hertel-k008371as-spiral-flute-tap-1-4-28-unf-bottoming-hss","provider":"Voomi Supply","version":"1.0","type":"link"}