Parlec 4001TRKC CAT40 Retention Knob 5/8-11 Thread

Product Description

The PARLEC 4001TRKC is a CAT40 retention knob designed to secure toolholders in CNC machining center spindles with automatic tool changers. Threaded 5/8-11 to mate with CAT40 toolholder drawbars, this Style B knob features a 90-degree angle radius and through-coolant capability with a 0.197-inch coolant hole diameter. Overall length is 2.3 inches, with a knob diameter of 0.588 inches and a pilot diameter of 0.635 inches. Weighing 1 pound, it is installed by CNC machinists and toolroom technicians as part of routine toolholder assembly or replacement.

This retention knob is suited for CAT40 toolholders used in vertical and horizontal machining centers equipped with automatic tool changers. The through-coolant design supports directed coolant flow to the cutting zone, making it appropriate for applications involving high-speed machining, deep-hole drilling, or other operations that benefit from internal coolant delivery. The Style B profile matches spindle and drawbar configurations that require this specific knob geometry.

Key Features

• CAT40 taper size for compatibility with standard CAT40 toolholder shanks
• 5/8-11 thread size for positive drawbar engagement
• Through-coolant capable with 0.197-inch coolant hole diameter
• 90-degree angle radius for proper drawbar seating
• Style B profile for specific spindle and drawbar fitment
• Compact flange thickness of 0.23 inches for precise toolholder registration

Compatibility

Designed as a replacement or spare retention knob for CAT40 toolholders used in CNC machining centers with 5/8-11 drawbar threads and Style B knob requirements.

Installation Notes

Retention knobs are installed by machinists or toolroom personnel during toolholder assembly. Always de-energize and lock out the machine spindle before servicing toolholders or installing retention knobs. Use the correct torque wrench and follow the toolholder manufacturer's torque specification for 5/8-11 retention knobs to avoid over-tightening, which can cause drawbar damage or difficult tool release. Inspect the knob threads and toolholder bore for damage or contamination before installation.