Accupro 88.613.50.AP CAT50 Retention Knob 1-8 Thread

Product Description

The 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.

This 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.

Key Features

• CAT50 taper interface with 1-8 UNC drawbar thread
• 45-degree angle radius, Style C geometry
• Through-coolant capable with 0.2362-inch coolant hole diameter
• High-torque retention design for demanding cutting applications
• 0.9055-inch knob diameter and 0.6693-inch neck diameter to CAT50 spec
• Compact 0.25-pound weight for minimal spindle mass addition

Compatibility

Designed as an OEM-style replacement retention knob for CAT50 spindle toolholder systems with a 1-8 UNC drawbar thread interface.

Installation Notes

Installation 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.