Parlec 4006TRK Retention Knob CAT40 5/8-11 Thread

Product Description

The PARLEC 4006TRK is a CAT40 retention knob designed to secure toolholders in CNC machining center spindles that use the CAT40 taper standard. It threads into the drawbar mechanism at 5/8-11 thread and pulls the toolholder firmly into the spindle taper during operation. The knob features a 45-degree angle radius, a 0.588-inch knob diameter, and an overall length of 2.45 inches. Style C geometry provides consistent seating and reliable clamping force across high-speed and high-load machining applications. Installation requires no special tooling beyond a standard torque wrench and is performed by machinists or tool crib technicians during toolholder assembly.

The 4006TRK is used in CAT40 toolholder assemblies on vertical and horizontal machining centers. It is suited for production shops, job shops, and toolroom environments where CAT40 is the predominant spindle interface. The knob threads directly into the pull stud pocket of a CAT40 toolholder body before the assembly is loaded into the spindle. Proper seating of the retention knob is critical to achieving full contact between the toolholder taper and the spindle bore, which directly affects runout and tool life.

Key Features

• CAT40 taper size for compatibility with standard CAT40 spindle systems
• 5/8-11 thread matches the drawbar specification common to CAT40 machining centers
• 45-degree angle radius for proper engagement with the spindle drawbar gripper fingers
• Style C knob geometry for consistent pull force and repeatable toolholder seating
• 0.392-inch neck diameter and 0.635-inch pilot diameter support accurate toolholder alignment
• Compact overall length of 2.45 inches with a 1.265-inch knob-to-flange dimension

Compatibility

Designed as a direct-fit retention knob for CAT40 toolholders requiring a 5/8-11 drawbar thread and Style C knob geometry.

Installation Notes

Retention knobs should be installed by a machinist or qualified tool crib technician. Power down and lock out the machining center before handling spindle toolholders or drawbar components. Thread the knob into the toolholder by hand first to confirm thread engagement, then torque to the toolholder manufacturer's specification using a calibrated torque wrench. Inspect threads and knob seating surfaces for wear or damage before each installation.