{"product_id":"value-collection-191-4j-reverse-counterbore-solid-carbide","title":"Value Collection 191-4J Reverse Counterbore Solid Carbide","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\u003cp\u003eThe VALUE COLLECTION 191-4J is a solid carbide reverse counterbore designed for spot facing operations on the blind side of a workpiece. With a 7\/16-inch cutting diameter and a 1\/8-inch pilot hole, this tool produces clean, flat bearing surfaces in locations that are inaccessible from the front. The 4-flute geometry promotes chip evacuation and surface finish quality. At 1\/2 inch overall length, it is sized for compact access in tight setups. A 1\/64-inch corner radius reduces edge stress at the counterbore shoulder. Machinists and toolroom technicians use this tool in metalworking, aerospace prep, and general machining applications.\u003c\/p\u003e\u003cp\u003eThis reverse counterbore is suited for holemaking and porting operations where a standard counterbore cannot reach. It is used in applications requiring a recessed seating surface on the back face of a part, such as bolt-hole spot facing in fabricated assemblies. The solid carbide construction supports use in harder workpiece materials and higher-speed setups. It is compatible with standard pilot model 185-2 and oversize pilot model 186-2, allowing the operator to match pilot fit to hole tolerance.\u003c\/p\u003e\u003ch4\u003eKey Features\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e7\/16-inch counterbore diameter for reverse spot facing operations\u003c\/li\u003e\n\u003cli\u003e1\/8-inch pilot hole diameter for precise tool alignment\u003c\/li\u003e\n\u003cli\u003e4-flute solid carbide construction for rigidity and wear resistance\u003c\/li\u003e\n\u003cli\u003e1\/2-inch overall length for compact, low-clearance setups\u003c\/li\u003e\n\u003cli\u003e1\/64-inch corner radius reduces stress concentration at the counterbore shoulder\u003c\/li\u003e\n\u003cli\u003eCompatible with standard pilot 185-2 and oversize pilot 186-2\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eCompatibility\u003c\/h4\u003e\u003cp\u003eAccepts standard pilot model number 185-2 and oversize pilot model number 186-2. Designed as a reverse counterbore for spot facing applications in metalworking and machining environments.\u003c\/p\u003e\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\u003cp\u003eThis tool is installed and operated by machinists or toolroom technicians using compatible pilot-and-arbor setups. Secure the workpiece fully before engaging the cutter to prevent movement during reverse spot facing. Power down the machine and verify zero spindle rotation before changing pilots or inspecting the cutting edges. Inspect carbide flutes for chipping before each use, as solid carbide is brittle under impact or lateral loading.\u003c\/p\u003e\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCounterbore Diameter\u003c\/strong\u003e: 7\/16 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePilot Hole Diameter\u003c\/strong\u003e: 1\/8 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNumber of Flutes\u003c\/strong\u003e: 4\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOverall Length\u003c\/strong\u003e: 1\/2 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCorner Radius\u003c\/strong\u003e: 1\/64 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTool Material\u003c\/strong\u003e: Solid Carbide\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard Pilot Compatibility\u003c\/strong\u003e: 185-2\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOversize Pilot Compatibility\u003c\/strong\u003e: 186-2\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUNSPSC Code\u003c\/strong\u003e: 23241603\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eStandard Information\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand\u003c\/strong\u003e: VALUE COLLECTION\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: 191-4J\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"VALUE COLLECTION","offers":[{"title":"Default Title","offer_id":68384086458674,"sku":"191-4J","price":273.43,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/2c85cfdd28a717ea88b5df179bbb934c_e650b6db-5c41-47a5-8b7d-7c14ec598552.jpg?v=1793901664","url":"https:\/\/voomisupply.com\/products\/value-collection-191-4j-reverse-counterbore-solid-carbide","provider":"Voomi Supply","version":"1.0","type":"link"}