Allied Machine 21431-0004 Indexable Spade Drill 4MT Taper Shank

Product Description

The ALLIED MACHINE AND ENGINEERING 21431-0004 is an indexable spade drill body designed for high-performance hole-making operations across a broad range of workpiece materials. It accepts interchangeable spade drill inserts and covers a drilling diameter range of 1.5 inches to 2.375 inches, with a maximum drilling depth of 4 inches. The body is constructed from steel and features a straight flute design, which promotes chip evacuation in short-hole drilling applications. The 4MT taper shank interfaces directly with machine tool spindles equipped with a Morse Taper No. 4 socket. This tool is installed and serviced by machining professionals and tool-room technicians working with drill presses, lathes, or machining centers.

This spade drill body is suited for general-purpose and high-performance drilling in universal workpiece material categories including cast iron, steel, non-ferrous metals, and non-metallic materials, corresponding to material codes K, M, N, and P. It is classified as a short-length body in the HP-C series, making it appropriate for rigid setups where minimizing tool overhang is a priority. Typical applications include production drilling in job shops, maintenance and repair operations, and manufacturing environments where a single drill body is used with multiple insert diameters to reduce tooling inventory.

Key Features

• Covers drilling diameters from 1.5 inches to 2.375 inches with interchangeable spade inserts
• 4MT taper shank for direct mounting in standard Morse Taper No. 4 spindle sockets
• Straight flute geometry supports chip flow in short-depth drilling operations
• Short body classification minimizes overhang and improves rigidity at the spindle
• HP-C series designation indicates high-performance design for universal workpiece materials
• No coolant-through capability — relies on external or flood coolant delivery

Compatibility

Designed as an OEM-style replacement and standard spade drill body compatible with machine tool spindles equipped with a 4MT (Morse Taper No. 4) socket. Accepts interchangeable spade drill inserts sized for the 1.5 inch to 2.375 inch diameter range within the HP-C series.

Installation Notes

Installation is performed by machinists or toolroom technicians familiar with Morse Taper tooling. Before inserting or removing the drill body, ensure the machine spindle is fully stopped and locked out per applicable machine safety procedures. Clean the taper shank and spindle socket thoroughly before seating to ensure proper contact and runout control. Do not use this body with coolant-through spindle systems, as this tool does not support internal coolant delivery.