{"product_id":"value-collection-231-4728-r8-collet-7-16-inch-steel","title":"Value Collection 231-4728 R8 Collet 7\/16 Inch Steel","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe VALUE COLLECTION 231-4728 is a 7\/16 inch R8 collet machined from steel for use in Bridgeport-style vertical milling machines and compatible spindles. It accepts a 7\/16-20 drawbar thread and holds tooling at a 7\/16 inch shank diameter. The collet is rated at 0.0007 inch total indicator runout (TIR), providing the concentricity control required for accurate milling operations. This type of collet is installed and serviced by machinists and tool-room professionals working on knee mills, bed mills, and similar manual or CNC-compatible R8-spindle equipment.\u003c\/p\u003e\n\u003cp\u003eR8 collets are the standard toolholding interface for Bridgeport and Bridgeport-style knee mills widely used in job shops, maintenance facilities, and vocational training environments. This collet is suited for holding 7\/16 inch shank end mills, drill bits, reamers, and other straight-shank cutting tools. It is appropriate for both roughing and finishing passes where consistent tool runout matters. Each package contains one collet.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e7\/16 inch bore diameter for straight-shank tooling\u003c\/li\u003e\n  \u003cli\u003eR8 taper profile fits Bridgeport-style spindles\u003c\/li\u003e\n  \u003cli\u003e7\/16-20 drawbar thread for secure spindle engagement\u003c\/li\u003e\n  \u003cli\u003e0.0007 inch TIR for reliable concentricity in milling applications\u003c\/li\u003e\n  \u003cli\u003eSteel construction for durability under milling loads\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eDesigned as an OEM-style replacement R8 collet for Bridgeport-style vertical knee mills and other manual or CNC milling machines equipped with an R8 spindle taper and a 7\/16-20 drawbar thread.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eR8 collets are installed and removed by a qualified machinist. Power down and lock out the machine spindle before changing collets. Clean the spindle bore and collet taper of chips and oil before seating the collet to maintain TIR accuracy. Tighten the drawbar to the mill manufacturer's recommended procedure using an appropriate wrench — do not overtighten, as this can damage the collet or spindle bore.\u003c\/p\u003e\n\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCollet Type\u003c\/strong\u003e: R8\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBore Diameter\u003c\/strong\u003e: 7\/16 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDrawbar Thread Size\u003c\/strong\u003e: 7\/16-20 in\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTotal Indicator Runout (TIR)\u003c\/strong\u003e: 0.0007 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaterial\u003c\/strong\u003e: Steel\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 0.56 pounds\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePackage Quantity\u003c\/strong\u003e: 1\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: 231-4728\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"VALUE COLLECTION","offers":[{"title":"Default Title","offer_id":51693744718130,"sku":"231-4728","price":26.87,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/162781be1751ce1e2ad81ce31b6149c6.jpg?v=1788316847","url":"https:\/\/voomisupply.com\/products\/value-collection-231-4728-r8-collet-7-16-inch-steel","provider":"Voomi Supply","version":"1.0","type":"link"}