{"product_id":"techniks-21003-45c-cat40-retention-knob-5-8-11-thread","title":"Techniks 21003-45C CAT40 Retention Knob 5\/8-11 Thread","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe TECHNIKS 21003-45C is a CAT40 retention knob designed to secure toolholders in CAT40 spindle tapers on CNC machining centers. It features a 5\/8-11 threaded shank, a 45-degree angle radius, and a knob diameter of 0.59 inches with an overall length of 2.25 inches. Through-coolant capability allows cutting fluid to pass through the spindle for improved chip evacuation and tool life during high-speed or deep-pocket operations. This component is installed by CNC machinists and toolroom technicians as part of routine toolholder setup and maintenance.\u003c\/p\u003e\n\u003cp\u003eThis retention knob is suited for use in vertical and horizontal CNC machining centers equipped with CAT40 spindle interfaces. It is a direct-fit replacement or spare for standard CAT40 toolholder assemblies used in production machining, toolroom work, and job shop environments. The 5\/8-11 thread size is the standard specification for CAT40 retention knobs, making this a widely applicable component across common CAT40-compatible toolholders.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003eCAT40 taper size for compatibility with CAT40 spindle systems\u003c\/li\u003e\n  \u003cli\u003e5\/8-11 thread size  -  standard for CAT40 toolholder engagement\u003c\/li\u003e\n  \u003cli\u003e45-degree angle radius for proper spindle drawbar engagement\u003c\/li\u003e\n  \u003cli\u003e0.59-inch knob diameter with 2.25-inch overall length\u003c\/li\u003e\n  \u003cli\u003eThrough-coolant design supports directed coolant delivery to the cutting zone\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eDesigned as a standard replacement retention knob for CAT40 toolholders using a 5\/8-11 thread. Confirm thread size and angle radius match existing toolholder specifications before installation.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eRetention knobs are installed by CNC machinists or toolroom technicians using appropriate retention knob installation tooling  -  never impact tools, which can damage spindle components. Power down and lock out the machine spindle before any toolholder or retention knob service. Thread engagement should be confirmed to be full and consistent prior to placing the assembly into the spindle. Follow machine tool manufacturer guidelines for drawbar force and toolholder seating procedures.\u003c\/p\u003e\n\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTaper Size\u003c\/strong\u003e: CAT40\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThread Size\u003c\/strong\u003e: 5\/8-11\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAngle Radius\u003c\/strong\u003e: 45 degrees\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eKnob Diameter\u003c\/strong\u003e: 0.59 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOverall Length\u003c\/strong\u003e: 2.25 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThrough Coolant\u003c\/strong\u003e: Yes\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: TECHNIKS\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: 21003-45C\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"TECHNIKS","offers":[{"title":"Default Title","offer_id":52031708889394,"sku":"21003-45C","price":31.06,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/67fbc7d3b46c8039850dd420800e3eff.jpg?v=1790020297","url":"https:\/\/voomisupply.com\/products\/techniks-21003-45c-cat40-retention-knob-5-8-11-thread","provider":"Voomi Supply","version":"1.0","type":"link"}