Parlec 40TRK CAT40 Retention Knob 5/8-11 Thread Through Coolant

Product Description

The PARLEC 40TRK is a CAT40 retention knob designed to secure toolholders in CNC machining center spindles that use the CAT40 taper interface. It threads into the drawbar at 5/8-11 and locks the toolholder in place during cutting operations. The 40TRK features a 45-degree angle radius at the knob head and a through-coolant passage with a 0.281-inch coolant hole diameter, making it compatible with machines that deliver coolant through the spindle. At 1.68 inches overall length and 0.1 pounds, this is a standard Style A retention knob suited for production and job-shop environments. Machinists and toolroom technicians install this knob as a direct-fit component in CAT40 tooling assemblies.

The 40TRK is used in vertical and horizontal machining centers equipped with CAT40 spindle tapers. It is appropriate for both production and prototype environments where reliable toolholder retention and through-spindle coolant delivery are required. The 0.74-inch knob diameter, 0.635-inch pilot diameter, and 0.64-inch knob-to-flange length conform to standard CAT40 geometry, ensuring consistent drawbar engagement across machines built to that specification. This knob is installed in the threaded bore at the top of a CAT40 toolholder shank.

Key Features

• CAT40 taper size for use with standard CAT40 toolholders and spindles
• 5/8-11 thread engages standard CAT40 drawbar hardware
• Through-coolant capable with a 0.281-inch coolant hole diameter for spindle-through coolant delivery
• 45-degree angle radius knob head conforms to Style A geometry
• 0.49-inch neck diameter and 0.635-inch pilot diameter provide accurate seating and drawbar alignment
• Lightweight at 0.1 pounds with a compact 1.68-inch overall length

Compatibility

Designed as a direct-fit retention knob for CAT40 toolholders using a 5/8-11 drawbar thread, compatible with CNC machining center spindles built to the CAT40 taper standard.

Installation Notes

Installation is performed by machinists or toolroom technicians using a retention knob wrench or appropriate spanner. The spindle must be fully stopped and the machine placed in an e-stop or lockout/tagout state before handling toolholders or retention hardware. Torque the knob to the toolholder manufacturer specification using a calibrated torque tool. Inspect the knob threads and toolholder bore threads for damage or contamination before assembly to avoid drawbar engagement issues.