{"product_id":"value-collection-191-4k-reverse-counterbore-solid-carbide","title":"Value Collection 191-4K Reverse Counterbore Solid Carbide","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe VALUE COLLECTION 191-4K is a solid carbide reverse counterbore designed for spot facing operations on the reverse or blind side of a workpiece. With a 7\/16-inch counterbore diameter, a 5\/32-inch pilot hole diameter, and four flutes, this tool delivers clean, flat bearing surfaces in applications where standard counterbores cannot reach. The 1\/2-inch overall length makes it compact and suitable for confined-space holemaking. Machinists and tool and die professionals working in aerospace, automotive, or general manufacturing will find this tool well suited to precision back-spotfacing tasks.\u003c\/p\u003e\n\u003cp\u003eThis reverse counterbore is used in metalworking and machining environments where a fastener seat or flat bearing surface must be created on an inaccessible face. It is typically installed in a CNC machining center or manual milling setup. The tool accepts a standard pilot or an oversize pilot, allowing the operator to select the fit that matches the drilled hole condition. Applications include back-spotfacing for bolt clearance, flush-mounting hardware, and similar precision holemaking operations in both production and maintenance settings.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003eSolid carbide construction for hardness, wear resistance, and dimensional stability in demanding cuts\u003c\/li\u003e\n  \u003cli\u003e7\/16-inch counterbore diameter with a 5\/32-inch pilot hole for precise centering\u003c\/li\u003e\n  \u003cli\u003eFour-flute geometry for improved chip evacuation and surface finish\u003c\/li\u003e\n  \u003cli\u003e1\/64-inch corner radius reduces stress concentration at the seat transition\u003c\/li\u003e\n  \u003cli\u003eCompatible with standard pilot model 185-3 and oversize pilot model 186-3\u003c\/li\u003e\n  \u003cli\u003eCompact 1\/2-inch overall length suited for tight-clearance reverse spotfacing\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eAccepts standard pilot model number 185-3 and oversize pilot model number 186-3. Designed as an OEM-style replacement or direct-use reverse counterbore for holemaking setups requiring back-spotfacing with a 5\/32-inch pilot and 7\/16-inch seat diameter.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eInstallation and operation should be performed by a qualified machinist familiar with reverse counterboring procedures. Power down and lock out the machine spindle before changing or securing the pilot in the tool body. Use appropriate cutting fluid for the workpiece material to extend tool life and maintain surface finish. Follow shop safety protocols and applicable machining standards when operating carbide cutting tools at speed.\u003c\/p\u003e\n\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\n\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: 5\/32 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOverall Length\u003c\/strong\u003e: 1\/2 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNumber of Flutes\u003c\/strong\u003e: 4\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 Model Compatibility\u003c\/strong\u003e: 185-3\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOversize Pilot Model Compatibility\u003c\/strong\u003e: 186-3\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAircraft Style\u003c\/strong\u003e: No\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eUNSPSC Code\u003c\/strong\u003e: 23241603\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: VALUE COLLECTION\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: 191-4K\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"VALUE COLLECTION","offers":[{"title":"Default Title","offer_id":68386146517298,"sku":"191-4K","price":174.64,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/2c85cfdd28a717ea88b5df179bbb934c_254a5f24-f043-49b3-a1f1-b9b2f1f1a10a.jpg?v=1793903106","url":"https:\/\/voomisupply.com\/products\/value-collection-191-4k-reverse-counterbore-solid-carbide","provider":"Voomi Supply","version":"1.0","type":"link"}