Helical Solutions 84021 Corner Radius End Mill 1/16in 4 Flute

Product Description

The HELICAL SOLUTIONS 84021 is a 4-flute, solid carbide corner radius end mill engineered for high-efficiency machining in demanding materials. It features a 1/16 inch mill diameter, a 0.0100 inch corner radius, and a 5/16 inch length of cut (0.3120 inches decimal). The Tplus PVD coating extends tool life and improves wear resistance when cutting stainless steel, high-temperature alloys, and hardened steel. A variable index geometry reduces harmonic vibration, making it well-suited for aggressive material removal and finish passes in a single tool path. This end mill is a single-end, centercutting design with right-hand flute direction and right-hand cutting direction.

The 84021 is designed for use in CNC milling operations where tight tolerances and surface finish are critical. Its extra-long overall length of 2.5 inches and 1/4 inch straight-cylindrical shank make it compatible with high-precision toolholders. Primary applications include roughing and finishing passes in stainless steel, superalloys, titanium, and hard materials. Secondary workpiece materials include steel and cast iron. It fits into HSM (high-speed machining) workflows where rigidity, runout control, and coating performance are priorities. This tool is intended for use by experienced machinists and CNC programmers working in precision manufacturing environments.

Key Features

• Solid carbide construction for rigidity and dimensional stability in hard-material cutting
• Tplus PVD coating rated for stainless steel, high-temperature alloys, and hardened steel
• Variable index pitch reduces chatter and harmonic vibration during cutting
• Centercutting design allows plunge entry without a pre-drilled hole
• Corner radius of 0.0100 inch reduces stress concentration at the cutting edge
• Maximum TIR of 0.0005 inch ensures consistent runout in high-precision toolholders

Compatibility

Designed for use with high-precision toolholders as part of the HSM-4 series. Primary workpiece materials are stainless steel, superalloys, and titanium (material codes M, S, H). Secondary workpiece materials include steel and cast iron (material codes P, K).

Installation Notes

Installation should be performed by a qualified machinist or CNC programmer familiar with end mill tooling. Seat the 1/4 inch shank fully in a high-precision toolholder and torque the collet or set screw to the toolholder manufacturer specification. Verify runout with a dial indicator before cutting, keeping TIR within the 0.0005 inch maximum. Always ensure the machine spindle is fully stopped before changing or inspecting tooling.