Iscar 4503110 Retention Knob CAT40 5/8-11 Thread

Product Description

The ISCAR 4503110 is a CAT40 retention knob designed to secure toolholders in CNC machining center spindles with a 5/8-11 threaded pull stud interface. At 2.25 inches overall length with a 0.59 inch knob diameter and a 0.39 inch neck diameter, this knob is built for reliable clamping force transfer between the drawbar and toolholder. A through-coolant design with a 0.217 inch coolant hole diameter allows directed coolant flow directly through the spindle assembly. Machinists and tool crib personnel handling CAT40 tooling will find this a straightforward OEM-style replacement or spare component.

This retention knob is used in vertical and horizontal CNC machining centers equipped with CAT40 spindle tapers. The 5/8-11 thread is the standard fastening interface for CAT40 toolholders. The knob-to-flange length of 1.266 inches positions the knob correctly for proper drawbar engagement. Through-coolant capability makes this knob suitable for high-pressure coolant spindle setups where coolant delivery through the tool is required for deep-hole drilling or high-speed machining operations.

Key Features

• CAT40 taper size for standard CNC machining center spindle compatibility
• 5/8-11 threaded interface for secure drawbar engagement
• Through-coolant design with 0.217 inch coolant hole diameter
• 0.59 inch knob diameter and 0.39 inch neck diameter for proper fitment geometry
• 1.266 inch knob-to-flange length ensures correct drawbar pull depth
• Lightweight at 0.05 pounds for minimal spindle load contribution

Compatibility

Designed as an OEM-style replacement retention knob for CAT40 toolholders requiring a 5/8-11 thread pull stud with through-coolant capability.

Installation Notes

Installation should be performed by a qualified machinist or toolroom technician with the machine fully powered down and the spindle locked. The retention knob should be torqued to the toolholder manufacturer's specified value using an appropriate pull stud wrench — do not use impact tools. Verify coolant passage alignment before reassembling the toolholder into the spindle. Inspect threads for wear or damage before each installation.