{"product_id":"kennametal-1026729-retention-knob-bt40-5-8-11-thread","title":"Kennametal 1026729 Retention Knob BT40 5\/8-11 Thread","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe KENNAMETAL 1026729 is a retention knob designed for BT40 taper toolholders used in CNC machining centers. It threads into the drawbar mechanism of the spindle to secure the toolholder during cutting operations. The knob features a 5\/8-11 thread size, a 45-degree angle radius at the flange contact, and a knob diameter of 0.589 inches. Overall length is 2.25 inches. This hardware is installed by CNC machine operators, tool crib technicians, and maintenance machinists performing toolholder setup or replacement on BT40-spindle machines.\u003c\/p\u003e\n\u003cp\u003eThis retention knob is suited for use in vertical and horizontal machining centers equipped with BT40 spindle tapers. It is a direct replacement component installed when a knob shows wear, cross-threading, or fails torque inspection. The neck diameter measures 0.392 inches, the pilot diameter is 0.636 inches, and the knob-to-flange length is 1.264 inches. No through-coolant feature is present on this knob, making it appropriate for dry or flood-coolant toolholder configurations that route coolant externally.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003eBT40 taper specification for compatibility with BT40 spindle drawbar systems\u003c\/li\u003e\n  \u003cli\u003e5\/8-11 thread size for secure engagement with standard BT40 drawbar pull studs\u003c\/li\u003e\n  \u003cli\u003e45-degree angle radius at flange contact for proper seating and pull force distribution\u003c\/li\u003e\n  \u003cli\u003e0.636-inch pilot diameter provides positive centering within the toolholder bore\u003c\/li\u003e\n  \u003cli\u003eCompact 2.25-inch overall length suits standard BT40 toolholder geometry\u003c\/li\u003e\n  \u003cli\u003eNo through-coolant port  -  suited for external coolant delivery setups\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eDesigned as an OEM-style replacement retention knob for BT40 taper toolholders using a 5\/8-11 thread drawbar interface.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eRetention knobs are installed by machinists or tool crib personnel. Always remove the toolholder from the spindle and ensure the machine is locked out and the spindle is fully de-energized before replacing a retention knob. Use the manufacturer-recommended torque procedure for BT40 pull studs  -  do not over-torque, as this can deform the knob or damage the toolholder bore. Inspect the mating drawbar threads for wear or damage before installing a new knob.\u003c\/p\u003e\n\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTaper Size\u003c\/strong\u003e: BT40\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: 0.589 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePilot Diameter\u003c\/strong\u003e: 0.636 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNeck Diameter\u003c\/strong\u003e: 0.392 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eKnob to Flange Length\u003c\/strong\u003e: 1.264 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: No\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 0.19 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: KENNAMETAL\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: 1026729\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"KENNAMETAL","offers":[{"title":"Default Title","offer_id":51739775402290,"sku":"1026729","price":73.33,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/ac76a2768fb07368c009dd316427e623.jpg?v=1788818727","url":"https:\/\/voomisupply.com\/products\/kennametal-1026729-retention-knob-bt40-5-8-11-thread","provider":"Voomi Supply","version":"1.0","type":"link"}