Allied Machine 21821-0004 Indexable Spade Drill 4MT Taper

Product Description

The ALLIED MACHINE AND ENGINEERING 21821-0004 is an indexable spade drill body designed for high-performance hole-making in a wide range of workpiece materials. Built to the HP-B series standard, this tool accepts interchangeable spade drill inserts and accommodates drill diameters from 1-1/4 inches to 1-3/4 inches. The 4MT taper shank with a shank diameter of 1.231 inches mounts directly into compatible taper-shank spindles and tool holders. Through-coolant delivery via dual radial entry ports keeps cutting edges cool and aids chip evacuation during deep-hole operations. The tool body is constructed from steel and is suited for use by machinists and tool-room professionals working in production or job-shop environments.

This spade drill body is intended for universal workpiece material applications, including steel, cast iron, aluminum, and non-ferrous metals, as indicated by the K, M, N, and P material code classification. The straight flute design provides a rigid body well suited to standard drilling operations in vertical machining centers, lathes, and horizontal boring mills equipped with 4MT taper spindles. The 8-1/8-inch flute length supports a maximum drilling depth of 8-1/8 inches, while the 14-11/16-inch overall length gives clearance for deep-bore setups. A 10-21/32-inch body length and 4-7/8-inch shank length round out the standard-length configuration of this HP-B series tool.

Key Features

• Diameter range of 1-1/4 inches to 1-3/4 inches accommodates multiple insert sizes in one body
• Through-coolant via dual radial entry ports (1/4 inch NPT thread) for efficient chip evacuation and edge cooling
• 4MT taper shank with 1.231-inch shank diameter for direct spindle mounting
• Straight flute geometry provides body rigidity for standard deep-hole drilling
• HP-B series designation; compatible with 2T-4SR rotary coolant adapter
• Steel body construction rated for high-performance cutting duty

Compatibility

Compatible with the 2T-4SR rotary coolant adapter. Designed for use with HP-B series indexable spade drill inserts. Fits machine spindles accepting a 4MT taper shank interface.

Installation Notes

Installation should be performed by a qualified machinist or tooling technician. Ensure the machine spindle is fully powered down and locked out before mounting or removing the tool body. Confirm the taper bore and shank are clean and free of chips or burrs before seating to ensure proper contact and runout. Connect coolant supply lines to the 1/4 inch NPT ports using fittings rated for the system operating pressure before resuming cutting operations.