Parlec 4004TRKC Retention Knob BT40 M16 X 2.00 Through Coolant

Product Description

The PARLEC 4004TRKC is a BT40 retention knob designed to secure toolholders in BT40 spindle interfaces on CNC machining centers. It threads into the toolholder drawbar at M16 x 2.00 and seats against the spindle with a 60-degree angle radius for consistent clamping force and accurate tool seating. The knob features a through-coolant passage with a 0.197-inch coolant hole diameter, allowing coolant delivery directly through the spindle when the machine and toolholder support it. At 2.36 inches overall length and 0.145 pounds, it is a direct-fit hardware component installed by CNC machinists and toolroom technicians.

This retention knob is used in BT40 toolholder assemblies on vertical and horizontal machining centers equipped with BT40 spindles. The Style C designation refers to the knob geometry, which suits standard BT40 toolholders requiring M16 x 2.00 thread engagement. The through-coolant design makes it well-suited for applications where internal coolant delivery is required, such as drilling, reaming, and high-speed milling operations where flood coolant alone is insufficient.

Key Features

• BT40 taper interface with M16 x 2.00 thread for standard BT40 toolholder compatibility
• 60-degree angle radius for consistent and repeatable spindle clamping engagement
• Through-coolant capable with 0.197-inch coolant hole diameter
• Style C geometry with 0.669-inch pilot diameter for precise toolholder alignment
• Compact 0.588-inch knob diameter and 2.36-inch overall length for direct replacement fitment
• Lightweight at 0.145 pounds, minimizing added mass in high-speed spindle assemblies

Compatibility

Designed for use with BT40 toolholders requiring an M16 x 2.00 retention knob thread. Specific toolholder compatibility should be confirmed against the toolholder manufacturer's retention knob specification before installation.

Installation Notes

Retention knobs are installed by machinists or toolroom technicians during toolholder assembly. The spindle must be fully de-energized and the machine placed in a safe state before any toolholder or retention knob service. Use the correct spanner or retention knob wrench to achieve proper seating torque per the toolholder manufacturer's specification. Do not overtighten, as this can distort the toolholder taper or damage the drawbar thread.