Parlec 40NTRK Retention Knob CAT40 5/8-11 Thread

Product Description

The PARLEC 40NTRK is a Style A retention knob designed for CAT40 taper toolholders used in CNC machining centers. It threads into the drawbar end of the toolholder with a 5/8-11 thread and locks the toolholder securely into the machine spindle during automatic tool changes. The knob features a 45-degree angle radius, a knob diameter of 0.74 inches, and an overall length of 1.68 inches. Machining center technicians and tool crib personnel install these as standard components when assembling or replacing CAT40 toolholder pull studs.

This retention knob fits CAT40 taper toolholders used in vertical and horizontal CNC machining centers equipped with automatic tool changers. It is suited for production shops, job shops, and maintenance applications where worn or damaged pull studs need to be replaced to maintain consistent clamping force and spindle engagement. The 0.635-inch pilot diameter and 0.49-inch neck diameter are sized to the CAT40 standard, and the 0.44-inch knob-to-flange length positions the knob correctly within the spindle drawbar system.

Key Features

• CAT40 taper size for use with standard CAT40 toolholders
• 5/8-11 thread engages the toolholder drawbar thread directly
• 45-degree angle radius for proper spindle gripper contact
• Style A configuration with 0.74-inch knob diameter
• 0.635-inch pilot diameter for accurate toolholder alignment
• Compact overall length of 1.68 inches fits standard CAT40 pull stud pockets

Compatibility

Designed as a replacement retention knob for CAT40 taper toolholders with a 5/8-11 drawbar thread, Style A configuration.

Installation Notes

Retention knobs are installed by tool crib technicians or machining center operators. Power down the machine and relieve any drawbar pressure before removing or installing a retention knob. Use the appropriate spanner wrench or retention knob installation tool to achieve proper torque - do not use pliers or improvised tools that can damage the thread or knob geometry. Inspect the toolholder thread for wear or damage before installing a new knob.