Collis Tool 68049 End Mill Holder NMTB40 5/16 Inch Bore

Product Description

The COLLIS TOOL 68049 is an end mill holder designed for use with NMTB40 taper shank spindles on vertical and horizontal milling machines. It accepts end mills with a 5/16 inch bore and provides a 2.5 inch projection from the spindle face, giving the cutting tool adequate clearance for a wide range of milling operations. The nose diameter measures 1 inch. This holder is a solid, precision-machined toolholder used by machinists and CNC operators to securely mount end mills in milling machine spindles. It uses a 5/8-11 drawbar thread for positive retention in the spindle.

The 68049 is suited for use on knee mills, Bridgeport-style machines, and other milling centers equipped with an NMTB40 (National Machine Tool Builders No. 40) taper spindle. The 2.5 inch projection makes it appropriate for general-purpose end milling, slotting, and profiling where moderate tool extension is needed. Through-coolant is not supported. This holder is typically selected by machinists, tool room operators, and CNC setup technicians when setting up end mill tooling on NMTB40 spindle machines.

Key Features

• NMTB40 taper shank for direct spindle mounting on compatible machines
• 5/16 inch bore accommodates standard 5/16 inch shank end mills
• 2.5 inch projection from spindle face for clearance in typical milling setups
• 1 inch nose diameter for secure tool clamping
• 5/8-11 drawbar thread for positive spindle retention
• No through-coolant - external coolant delivery required if needed

Compatibility

Designed for use with milling machine spindles configured to the NMTB40 taper standard and equipped with a 5/8-11 drawbar thread. Accepts end mills with a 5/16 inch straight shank.

Installation Notes

Installation is performed by qualified machinists or CNC setup technicians. Power down and lock out the machine spindle before inserting or removing any toolholder. Ensure the spindle taper and toolholder taper are clean and free of chips or oil before seating. Tighten the drawbar to the machine manufacturer's specified torque using the appropriate drawbar wrench - do not over-tighten or under-tighten.