{"product_id":"accupro-88-613-50-ap-cat50-retention-knob-1-8-thread","title":"Accupro 88.613.50.AP CAT50 Retention Knob 1-8 Thread","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\u003cp\u003eThe ACCUPRO 88.613.50.AP is a CAT50 retention knob designed to secure toolholders in CAT50 spindle interfaces on CNC machining centers. It threads into the drawbar mechanism and clamps the toolholder taper firmly against the spindle during high-speed cutting operations. Built to Style C geometry with a 45-degree angle radius, this knob features a high-torque design and through-coolant capability with a 0.2362-inch coolant hole diameter. The 1-8 UNC thread engages the drawbar with positive holding force. At 3.3524 inches overall length and 0.25 pounds, it is a direct-replacement component for worn or damaged retention hardware in production machining environments.\u003c\/p\u003e\u003cp\u003eThis retention knob is suited for CAT50 toolholder applications in vertical and horizontal machining centers running production or job-shop operations. The through-coolant feature makes it compatible with high-pressure coolant systems that deliver fluid directly through the spindle to the cutting zone. The 0.9055-inch knob diameter, 0.6693-inch neck diameter, and 1.7776-inch knob-to-flange length are dimensioned to CAT50 standard geometry. Machine tool maintenance technicians and CNC setup personnel install this component as part of routine toolholder service or spindle rebuilds.\u003c\/p\u003e\u003ch4\u003eKey Features\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003eCAT50 taper interface with 1-8 UNC drawbar thread\u003c\/li\u003e\n\u003cli\u003e45-degree angle radius, Style C geometry\u003c\/li\u003e\n\u003cli\u003eThrough-coolant capable with 0.2362-inch coolant hole diameter\u003c\/li\u003e\n\u003cli\u003eHigh-torque retention design for demanding cutting applications\u003c\/li\u003e\n\u003cli\u003e0.9055-inch knob diameter and 0.6693-inch neck diameter to CAT50 spec\u003c\/li\u003e\n\u003cli\u003eCompact 0.25-pound weight for minimal spindle mass addition\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eCompatibility\u003c\/h4\u003e\u003cp\u003eDesigned as an OEM-style replacement retention knob for CAT50 spindle toolholder systems with a 1-8 UNC drawbar thread interface.\u003c\/p\u003e\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\u003cp\u003eInstallation and removal of retention knobs should be performed by a qualified CNC machinist or machine tool technician with the machine powered down and the spindle fully de-energized. Use a proper retention knob wrench sized for CAT50 hardware to avoid damaging the knob or drawbar threads. Inspect drawbar threads for wear before installation. Do not overtighten, as doing so can distort the toolholder taper seating and affect runout.\u003c\/p\u003e\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eTaper Size\u003c\/strong\u003e: CAT50\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread Size\u003c\/strong\u003e: 1-8 UNC\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStyle\u003c\/strong\u003e: C\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAngle Radius\u003c\/strong\u003e: 45 degrees\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOverall Length\u003c\/strong\u003e: 3.3524 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eKnob Diameter\u003c\/strong\u003e: 0.9055 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNeck Diameter\u003c\/strong\u003e: 0.6693 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eKnob to Flange Length\u003c\/strong\u003e: 1.7776 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlange Thickness\u003c\/strong\u003e: 1.3839 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCoolant Hole Diameter\u003c\/strong\u003e: 0.2362 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThrough Coolant\u003c\/strong\u003e: Yes\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHigh Torque\u003c\/strong\u003e: Yes\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 0.25 pounds\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eStandard Information\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand\u003c\/strong\u003e: ACCUPRO\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: 88.613.50.AP\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"ACCUPRO","offers":[{"title":"Default Title","offer_id":51732186726706,"sku":"88.613.50.AP","price":59.91,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/7cf71042775dd07dd5138442ebbdd704.jpg?v=1788740180","url":"https:\/\/voomisupply.com\/products\/accupro-88-613-50-ap-cat50-retention-knob-1-8-thread","provider":"Voomi Supply","version":"1.0","type":"link"}