Parlec 4005TRKC Retention Knob CAT40 5/8-11 Thread

Product Description

The PARLEC 4005TRKC is a Style C retention knob designed for CAT40 toolholders used in CNC machining centers. It features a 5/8-11 threaded shank that engages the drawbar mechanism to secure the toolholder in the spindle during operation. The knob includes a through-coolant passage with a 0.157-inch coolant hole diameter, allowing pressurized coolant delivery directly through the toolholder. Overall length is 2.3 inches, knob diameter is 0.588 inches, and the 45-degree angle radius on the knob head is engineered to seat correctly against the drawbar. This part is installed by CNC machinists and toolroom technicians in production and job-shop environments.

The 4005TRKC is suited for CAT40 toolholders requiring a 5/8-11 drawbar thread. The through-coolant design makes it appropriate for applications where directed coolant flow to the cutting zone is needed, such as deep-hole drilling, reaming, or high-speed milling. The pilot diameter of 0.635 inches and knob-to-flange length of 1.268 inches are sized to the CAT40 standard, ensuring consistent pull-force distribution across compatible spindle systems.

Key Features

• CAT40 taper size for use with standard CAT40 toolholders
• 5/8-11 thread engages directly with the machining center drawbar
• Through-coolant capable with a 0.157-inch coolant hole diameter
• 45-degree angle radius head geometry for correct drawbar seating
• Style C knob profile with 0.393-inch neck diameter and 0.635-inch pilot diameter
• 0.588-inch knob diameter and 0.130-inch flange thickness to CAT40 specification

Compatibility

Designed as a replacement or spare retention knob for CAT40 toolholders with a 5/8-11 drawbar thread. Specific machine and toolholder compatibility should be verified against the spindle manufacturer drawbar thread specification before installation.

Installation Notes

Retention knobs are installed and replaced by CNC machinists or toolroom technicians. Power down the machining center and release spindle pressure before servicing the drawbar or toolholder assembly. Use the correct torque wrench and toolholder fixture to tighten the retention knob to the toolholder manufacturer specified torque value - do not over-torque or under-torque, as either condition can cause toolholder pull-out or spindle damage. Inspect the knob threads and toolholder bore for damage or contamination before assembly.