Iscar 4503112 Retention Knob CAT50 1-8 Thread Through Coolant

Product Description

The ISCAR 4503112 is a CAT50 retention knob designed for securing tool holders in CAT50 spindle tapers on CNC machining centers. It features a 1-8 inch thread, a 45-degree angle radius, and a knob diameter of 0.906 inches with an overall length of 3.346 inches. The through-coolant design includes a 0.236-inch coolant hole diameter, enabling direct coolant delivery to the cutting zone. Machining centers in production and job-shop environments rely on properly torqued retention knobs like this one to maintain drawbar pull force and prevent tool pull-out under heavy cutting loads. This part weighs 1 pound.

This retention knob is suited for CNC vertical and horizontal machining centers equipped with CAT50 spindle tooling systems. It is a direct replacement component used during tool holder maintenance or when an existing retention knob shows wear, thread damage, or fails drawbar pull testing. The through-coolant passage supports flood or high-pressure coolant strategies common in ferrous and non-ferrous machining applications. Installation is performed by tool crib technicians or machine operators during standard tool holder assembly.

Key Features

• CAT50 taper size for use in CAT50 spindle machining systems
• 1-8 inch thread specification for compatibility with standard CAT50 drawbars
• 45-degree angle radius for proper seating against the drawbar contact surface
• Through-coolant capable with a 0.236-inch coolant hole diameter
• Knob to flange length of 1.772 inches and neck diameter of 0.670 inches
• Overall length of 3.346 inches for standard CAT50 tool holder fitment

Compatibility

Designed as an OEM-style replacement retention knob for CAT50 taper tool holders using a 1-8 inch drawbar thread.

Installation Notes

Retention knobs are installed by tool crib personnel or qualified machine operators using a retention knob wrench and a torque wrench calibrated to the tool holder manufacturer's specification. Always power down and lock out the machining center spindle before servicing tool holders or retention knobs. Do not over-torque the retention knob, as excess torque can deform the tool holder taper and reduce spindle contact accuracy. Inspect the drawbar and spindle bore for debris or damage before reinstalling.