Allied 1C21T-.859 Spade Drill Insert 55/64 in Solid Carbide

Product Description

The ALLIED MACHINE AND ENGINEERING 1C21T-.859 is a solid carbide spade drill insert designed for high-performance hole-making in demanding materials. Part of the T-A series, this insert measures 55/64 inches in diameter and seats in a Size 1 holder. The 132-degree point angle provides a self-centering entry that reduces thrust and improves hole accuracy. A PVD-applied TiN coating increases surface hardness and extends tool life in abrasive cutting conditions. Manufactured to C2 (K20) grade carbide, it delivers the rigidity and edge retention required for production drilling environments. The insert weighs 0.1 pounds.

This insert is suited for drilling stainless steel, cast iron, non-ferrous metals, super-alloys, and titanium. The T-A modular spade drill system is commonly used in CNC machining centers, lathes, and drill presses across metalworking, aerospace, energy, and general manufacturing applications. The Size 1 seat designation matches it to compatible T-A series holders, making it a direct drop-in insert for existing setups without retooling the holder assembly.

Key Features

• 55/64 inch diameter, Size 1 seat — fits T-A series spade drill holders directly
• 132-degree point angle for self-centering entry and reduced exit burr
• Solid carbide C2 (K20) grade construction for rigidity and wear resistance
• PVD TiN coating extends tool life in stainless steel, cast iron, and titanium
• Rated for primary workpiece material codes M, K, N, and S
• Thickness of 0.1563 inches for consistent seating and repeatability

Compatibility

Designed for use with T-A series Size 1 spade drill holders. Compatible primary workpiece materials include stainless steel (M), cast iron (K), non-ferrous metals (N), and super-alloys and titanium (S).

Installation Notes

Installation is performed by qualified machinists or toolroom technicians. Power down and lock out the machine spindle before inserting or removing spade drill inserts. Seat the insert fully and confirm secure clamping against the holder seat before running the spindle. Follow the tool manufacturer holder torque specifications and do not exceed recommended feed and speed parameters for the workpiece material being drilled.