Iscar 4503113 Retention Knob CAT50 1-8 Thread Through Coolant

Product Description

The ISCAR 4503113 is a CAT50 retention knob designed to secure tool holders in CNC machining centers that use the CAT50 taper standard. It threads directly into the drawbar mechanism of the spindle, locking the tool holder in place during operation. The knob features a 1-8 UNC thread, a 90-degree angle radius at the head, a knob diameter of 0.906 inches, and a through-coolant passage with a 0.236-inch coolant hole diameter. With an overall length of 3.346 inches and a neck diameter of 0.67 inches, this knob is a direct replacement component for machining center spindle maintenance. Installation is handled by CNC machine service technicians or tooling setup personnel.

This retention knob is suited for use in CNC vertical and horizontal machining centers equipped with a CAT50 spindle taper. It is appropriate for production shops, job shops, and manufacturing facilities running heavy-duty tooling that requires through-coolant delivery to the cutting tool. The through-coolant design supports applications where coolant must pass through the tool holder and cutting tool to improve chip evacuation and tool life. Knob-to-flange length measures 1.772 inches, which positions the tool holder correctly within the spindle for proper engagement.

Key Features

• CAT50 taper size for compatibility with standard CAT50 spindle systems
• 1-8 UNC thread engages the drawbar mechanism securely
• Through-coolant capable with a 0.236-inch coolant hole diameter
• 90-degree angle radius head for proper seating and pull-stud engagement
• Knob diameter of 0.906 inches and neck diameter of 0.67 inches for precise fitment
• Overall length of 3.346 inches with a knob-to-flange length of 1.772 inches

Compatibility

Designed as a direct-fit retention knob for CAT50 tool holders used in CNC machining centers with a 1-8 UNC drawbar thread and through-coolant spindle capability.

Installation Notes

Retention knobs should be installed by qualified CNC tooling or machine service personnel. Power down and lock out the machining center before accessing the spindle or changing retention hardware. Use the correct torque specification as defined by the machine tool builder or tool holder manufacturer — do not over-tighten, as improper torque can damage the drawbar or taper interface. Inspect the knob threads and tool holder threads for wear or damage before installation.