Parlec 4003TRK Retention Knob BT40 M16 X 2.00 Thread

Product Description

The PARLEC 4003TRK is a Style C retention knob designed for BT40 taper toolholders used in CNC machining centers. It features an M16 x 2.00 threaded shank that draws the toolholder securely into the spindle, and a 45-degree angle radius geometry at the knob head. With an overall length of 2.36 inches and a knob diameter of 0.588 inches, this retention knob delivers consistent clamping engagement for high-speed and high-torque milling applications. Installation requires correct torque procedure to seat the knob properly without damaging the toolholder threads. This part is a direct-fit component for CNC spindle systems using the BT40 interface standard.

The 4003TRK is used in production and job-shop CNC machining environments wherever BT40 toolholders are pulled into vertical or horizontal machining center spindles. The BT40 taper is widely used in mid-size machining centers running general-purpose milling, drilling, and boring operations. This retention knob is installed by CNC maintenance technicians and toolroom personnel during toolholder assembly or when replacing worn or damaged knobs. A pilot diameter of 0.669 inches and neck diameter of 0.393 inches provide accurate self-centering during assembly.

Key Features

• BT40 taper interface for compatibility with standard BT40 toolholders
• M16 x 2.00 thread size for secure spindle drawbar engagement
• 45-degree angle radius knob geometry for proper drawbar contact
• Style C configuration with 0.669-inch pilot diameter for self-centering fit
• Compact 2.36-inch overall length with 0.230-inch flange thickness
• Lightweight at 0.23 pounds for minimal added rotating mass

Compatibility

Designed as an OEM-style replacement retention knob for BT40 taper toolholders used in CNC machining center spindles equipped with an M16 x 2.00 drawbar thread.

Installation Notes

Retention knobs should be installed by qualified CNC toolroom or maintenance personnel. Power down and lock out the machining center before handling spindle components or toolholders. Thread the knob into the toolholder by hand first to confirm clean thread engagement, then torque to the toolholder manufacturer specification using an appropriate torque wrench. Inspect threads on both the knob and toolholder for wear or damage before reinstalling into an active spindle.