Collis Tool 68048 End Mill Holder NMTB40 1/4 Inch

Product Description

The COLLIS TOOL 68048 is an end mill holder designed for CNC machining centers and manual milling machines using the NMTB40 taper shank standard. It accepts end mills with a 1/4 inch hole diameter and provides 2.5 inches of projection from the gauge line, giving machinists controlled reach for a range of milling operations. The nose diameter measures 11/16 inch. This holder is a rigid, direct-mount tooling component installed by machinists and toolroom technicians to secure end mills in taper-spindle machines. It weighs 1.69 pounds and is a single-piece unit.

This end mill holder is suited for use in production and job-shop environments where NMTB40 (also known as National Machine Tool Builders 40-taper) spindle tooling is standard. Typical applications include face milling, slotting, and profiling operations on knee mills and older CNC vertical machining centers equipped with NMTB40 spindles. The 2.5 inch projection accommodates workpieces and fixtures that require additional clearance between the spindle nose and the cut zone. The drawbar thread size is 5/8-11, matching the standard retention stud for NMTB40 tooling.

Key Features

• NMTB40 taper shank for direct spindle mounting on compatible milling machines
• 1/4 inch hole diameter for standard end mill shanks
• 2.5 inch projection (decimal: 2.5000 inches) for extended reach applications
• 11/16 inch nose diameter for clearance in tight setups
• 5/8-11 drawbar thread size for secure retention
• No through-coolant - suited for dry or flood coolant applied externally

Compatibility

Designed for use with NMTB40 taper spindle machines requiring a 5/8-11 drawbar thread. Accepts 1/4 inch shank end mills. No specific machine model compatibility was provided by the manufacturer for this part.

Installation Notes

Installation is performed by qualified machinists or toolroom technicians. Before mounting or removing any toolholder, ensure the machine spindle is fully stopped and the machine is in a safe, locked-out state per applicable shop safety procedures. Torque the drawbar to the spindle manufacturer's specification using the correct drawbar wrench - do not over-tighten or use impact tools on the drawbar. Inspect the taper bore and holder taper for nicks, chips, or contamination before seating the holder, as debris on the mating tapers can cause runout and premature wear.