Parlec 5005TRK Retention Knob CAT50 1-8 Thread

Product Description

The PARLEC 5005TRK is a CAT50 retention knob designed to secure toolholders in CNC machining center spindles that use the CAT50 taper standard. It threads into the drawbar mechanism with a 1-8 UNC thread and holds the toolholder firmly seated during cutting operations. The knob features a 45-degree angle radius, a knob diameter of 0.904 inches, and an overall length of 3.31 inches. Style C geometry fits a defined range of CAT50 toolholder shanks. Machinists and toolroom technicians install this component as a direct replacement or spare during toolholder setup and maintenance.

This retention knob is used in vertical and horizontal CNC machining centers equipped with CAT50 spindles. CAT50 is a common taper in heavy-duty production machining environments where larger toolholders and higher torque demands are present. The knob is installed into the threaded pull stud receptacle of a CAT50 toolholder shank, then engaged by the machine spindle drawbar to clamp the toolholder. No through-coolant feature is present on this knob, making it suited for standard dry or flood-coolant applications where internal coolant delivery through the pull stud is not required.

Key Features

• CAT50 taper size for compatibility with heavy-duty CNC spindle systems
• 1-8 UNC thread engages standard CAT50 drawbar pull systems
• 45-degree angle radius per Style C retention knob geometry
• 0.904-inch knob diameter with 1.026-inch pilot diameter for accurate seating
• 3.31-inch overall length with 0.667-inch neck diameter
• No through-coolant passage - suited for standard coolant delivery setups

Compatibility

Designed as an OEM-style replacement retention knob for CAT50 toolholders requiring a Style C pull stud with 1-8 UNC thread. Verify thread engagement and knob geometry against the toolholder manufacturer specification before installation.

Installation Notes

A licensed machinist or qualified toolroom technician should install this retention knob. Always ensure the CNC machine spindle drawbar is fully retracted and the machine is powered down and locked out before handling toolholders or pull studs. Use the correct retention knob wrench or spanner to achieve proper torque - consult the toolholder manufacturer torque specification for the CAT50 interface. Do not cross-thread the knob into the toolholder shank, as this can damage the thread and cause unsafe toolholder retention.