{"product_id":"techniks-21003-c-retention-knob-cat40-5-8-11-thread","title":"Techniks 21003-C Retention Knob CAT40 5\/8-11 Thread","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe TECHNIKS 21003-C is a CAT40 retention knob designed to secure tool holders in CAT40 spindle tapers on CNC machining centers. It features a 5\/8-11 threaded shank and a 45-degree angle radius that seats reliably against the drawbar mechanism inside the spindle. The knob diameter measures 0.74 inches with an overall length of 1.5 inches. Through-coolant capability is built in, allowing coolant flow through the spindle without obstruction. Machinists and tool crib technicians install this hardware as part of routine tooling changes or when replacing worn or damaged pull studs on CAT40 toolholders.\u003c\/p\u003e\n\u003cp\u003eThis retention knob is used in CNC milling and machining center applications that run CAT40 tooling. It fits standard CAT40 tool holders requiring a 5\/8-11 thread pull stud. Typical install scenarios include production shops, job shops, and maintenance environments where CAT40 spindle tooling is regularly changed or serviced. The through-coolant design suits applications where coolant-through spindles are in use, keeping the coolant path unobstructed during cutting operations.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003eCAT40 taper specification for compatibility with standard CAT40 spindle systems\u003c\/li\u003e\n  \u003cli\u003e5\/8-11 threaded shank for secure engagement with the drawbar\u003c\/li\u003e\n  \u003cli\u003e45-degree angle radius for consistent seating and pull force distribution\u003c\/li\u003e\n  \u003cli\u003eThrough-coolant design supports coolant-through spindle configurations\u003c\/li\u003e\n  \u003cli\u003eCompact 1.5 inch overall length with 0.74 inch knob diameter\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eDesigned as a replacement pull stud for CAT40 tool holders with a 5\/8-11 thread requirement and 45-degree angle radius drawbar engagement.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eInstallation is performed by qualified machinists or tool crib personnel. Always confirm the spindle is fully stopped and the machine is in a safe, locked-out state before changing or torquing retention knobs. Use the tool holder manufacturer's specified torque procedure and a retention knob wrench appropriate for the knob diameter. Inspect threads on both the retention knob and the tool holder for wear or damage before installation.\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\u003eOverall Length\u003c\/strong\u003e: 1.5 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eKnob Diameter\u003c\/strong\u003e: 0.74 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAngle Radius\u003c\/strong\u003e: 45 degrees\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThrough Coolant\u003c\/strong\u003e: Yes\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 0.1 pounds\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eUNSPSC Code\u003c\/strong\u003e: 27112800\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-C\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"TECHNIKS","offers":[{"title":"Default Title","offer_id":52077703725362,"sku":"21003-C","price":38.6,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/7360ca408658c6f07d2e1ebf5bd3a4c4.jpg?v=1790053612","url":"https:\/\/voomisupply.com\/products\/techniks-21003-c-retention-knob-cat40-5-8-11-thread","provider":"Voomi Supply","version":"1.0","type":"link"}