{"product_id":"heli-coil-a1191-4cnpf500-free-running-insert-1-4-28-unf","title":"Heli-coil A1191-4CNPF500 Free Running Insert 1\/4-28 Unf","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\u003cp\u003eThe HELI-COIL A1191-4CNPF500 is a free running helical wire thread insert designed to create or restore strong, durable internal threads in a tapped host material. Manufactured from 304 stainless steel with a primer-free finish, this insert measures 0.5 inches overall length and accepts a 1\/4-28 UNF thread. The tanged design allows for installation using a standard installation tool, with the tang providing the driving surface during insertion. This insert carries an 11-3\/8 free coil count and a 2D length-to-diameter ratio, making it suitable for applications that require reliable thread strength in a compact footprint. Machinists, maintenance technicians, and field service professionals commonly install these in metalworking and repair operations.\u003c\/p\u003e\u003cp\u003eFree running inserts of this type are used across industrial, mechanical, and maintenance applications where thread repair or thread reinforcement is needed. The 1\/4-28 UNF thread size is common in precision assemblies, automotive, aerospace ground support, and general manufacturing environments. The primer-free finish is suited for installations where no coating adhesion preparation is required. This insert is sold individually and is typically installed in quantities consistent with the application requirement.\u003c\/p\u003e\u003ch4\u003eKey Features\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e1\/4-28 UNF thread size for precision fine-thread applications\u003c\/li\u003e\n\u003cli\u003e304 stainless steel construction for corrosion resistance and strength\u003c\/li\u003e\n\u003cli\u003e0.5 inches overall length with a 2D length-to-diameter ratio\u003c\/li\u003e\n\u003cli\u003eTanged design for positive engagement during installation with a standard insert tool\u003c\/li\u003e\n\u003cli\u003ePrimer-free finish requires no additional surface preparation before installation\u003c\/li\u003e\n\u003cli\u003e11-3\/8 free coil count for consistent thread engagement across full insert length\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eCompatibility\u003c\/h4\u003e\u003cp\u003eDesigned as an OEM-style replacement or new-installation insert for any application requiring a 1\/4-28 UNF free running threaded insert in a properly prepared tapped bore.\u003c\/p\u003e\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\u003cp\u003eInstallation is performed using a compatible helical insert installation tool sized for 1\/4-28 UNF thread. The tang is used to drive the insert into the tapped hole and should be broken off after installation using a tang break-off tool where the application requires a tang-free bore. Ensure the host material is tapped to the correct STI (Screw Thread Insert) tap size before installation. Always de-energize or isolate any equipment before performing thread repair work on assembled components.\u003c\/p\u003e\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\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\u003eOverall Insert Length\u003c\/strong\u003e: 0.5 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLength to Diameter Ratio\u003c\/strong\u003e: 2D\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTang Type\u003c\/strong\u003e: Tanged\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNumber of Free Coils\u003c\/strong\u003e: 11-3\/8\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial\u003c\/strong\u003e: Stainless Steel\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial Grade\u003c\/strong\u003e: 304\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCoating\/Finish\u003c\/strong\u003e: Primer-Free\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNumber of Inserts\u003c\/strong\u003e: 1\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eStandard Information\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand\u003c\/strong\u003e: HELI-COIL\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: A1191-4CNPF500\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"HELI-COIL","offers":[{"title":"Default Title","offer_id":51972010869042,"sku":"A1191-4CNPF500","price":30.68,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/8af6d74b459270db98722f5fe2a11661.jpg?v=1789960884","url":"https:\/\/voomisupply.com\/products\/heli-coil-a1191-4cnpf500-free-running-insert-1-4-28-unf","provider":"Voomi Supply","version":"1.0","type":"link"}