HRC55 4 Flute Deep Groove Corner Radius End Mill R0.2 R0.5, Solid Carbide Extended Reach CNC Milling Cutter for Steel

HRC55 4 Flute Deep Groove Corner Radius End Mill

This HRC55 4 Flute Deep Groove Corner Radius End Mill is designed for precision CNC milling of hardened and pre-hardened steels. Featuring a solid carbide construction, extended reach design and precision corner radius geometry, it provides stable cutting performance in deep grooves, narrow cavities, side walls and other hard-to-reach machining areas.

The R0.2 and R0.5 corner radius options reinforce the cutting edge compared with a sharp-corner flat end mill, helping reduce edge chipping while maintaining excellent dimensional accuracy and surface quality. The small-diameter design is particularly suitable for detailed machining and narrow groove applications.

Key Features

• HRC55 hardness grade — suitable for hardened and pre-hardened steel machining
• 4-flute geometry — provides a good balance between cutting efficiency, rigidity and surface finish
• Deep groove design — suitable for narrow and deep machining features
• Corner radius R0.2 / R0.5 — improves cutting-edge strength and tool durability
• Small diameter D1 — suitable for precision machining of narrow grooves and detailed features
• Extended reach / reduced interference design — provides better access to deep cavities and recessed areas
• Solid carbide construction — high rigidity and excellent wear resistance
• Precision-ground cutting edges — designed for stable dimensional accuracy and consistent machining performance
• CNC machining compatible — suitable for machining centers, CNC mills and high-speed machining applications

Typical Applications

This cutter is especially suitable for:

Deep Groove Milling
Designed for machining narrow and deep grooves where standard-length end mills may have insufficient reach.

Deep Cavity & Pocket Milling
The extended design allows the tool to reach recessed areas while reducing interference between the holder and workpiece.

Side Wall & Shoulder Machining
The 4-flute geometry provides stable cutting and good surface finish during side milling.

Precision Corner Machining
The R0.2/R0.5 corner radius helps produce controlled transitions between the bottom and side walls while reducing sharp-edge chipping.

Die & Mold Machining
Suitable for precision machining of mold components, dies, inserts and complex hardened-steel components.

Small Feature Machining
The D1 small-diameter configuration is suitable for narrow slots, small pockets and detailed machining features.

Recommended Workpiece Materials

• Hardened Steel
• Pre-Hardened Steel
• Tool Steel
• Mold Steel
• Alloy Steel
• Carbon Steel
• Die Steel

Recommended hardness: up to approximately HRC55, depending on machine rigidity, workpiece condition, tool overhang and cutting parameters.

Product Specifications

Machining Advantages

The combination of 4-flute geometry, corner radius cutting edges and extended-reach construction makes this tool suitable for applications where both reach and cutting stability are important. The corner radius provides additional edge strength compared with a sharp-corner flat end mill, while the solid carbide substrate offers the rigidity required for precision machining.

For deep machining applications, the actual cutting parameters should be adjusted according to tool diameter, flute length, tool overhang, workpiece hardness, machine rigidity, spindle performance and cooling conditions.

Custom Sizes Available

Different diameters, flute lengths, corner radii, shank configurations and overall lengths can be customized according to your machining requirements.

For special dimensions or large-volume orders, please provide the workpiece material, hardness, machining depth, required tool diameter and application drawing for a suitable tooling recommendation.