HH(300) 2 flute micro long neck carbide square end mill with 0.3μm ultra-fine carbide and TiSiN PVD coating for deep, narrow machining in hardened and mold steel up to 60 HRC.
The HH(300) 2 flute micro long neck end mill is designed for machining small, deep and restricted features in hardened steel and mold steel.
Its micro-diameter cutting section provides access to fine features, while the long neck design creates additional clearance for deep grooves, recessed pockets and narrow cavities. A 0.3μm ultra-fine carbide substrate combined with TiSiN PVD coating supports high-speed machining and demanding dry or semi-dry cutting conditions.
The tool is suitable for hardened steel up to 60 HRC and can also be used for titanium alloys and nickel-based high-temperature alloys under appropriate conditions.
Product Highlights
Deep Micro Machining Applications
Deep Narrow Grooves
The micro cutting diameter allows access to narrow grooves, while the long neck provides the additional reach needed for deeper features.
Recessed Cavities
Suitable for small cavities and recessed areas where conventional micro end mills may not provide enough clearance.
Fine Mold Features
Designed for small ribs, pockets, steps and other precision mold features in hardened steel.
Deep Hardened-Steel Features
The HH(300) combines micro geometry with a hardened-steel capability up to 60 HRC, making it suitable for selected deep machining applications.
Micro Long Neck Geometry
Micro Cutting Diameter
The small cutting diameter is intended for fine features and restricted areas where a conventional end mill is too large.
Long Neck Clearance
The reduced neck section creates additional clearance behind the cutting area, helping the tool reach deeper features without unnecessary body interference.
Effective Length
For micro long-neck tools, the effective length is a critical selection factor. Use the shortest practical reach needed for the feature to maintain rigidity.
Tool Overhang
As tool extension increases, sensitivity to vibration and deflection also increases. A rigid setup and minimal practical overhang are important for stable machining.
Commercial micro long-neck tools commonly specify reach, cutting length, neck diameter and overall length separately because these dimensions directly affect deep-feature applications.
Why Use 2 Flutes for Micro Machining?
More Open Flute Space
The 2-flute configuration leaves more space around the cutting area, which can help manage chips in small-diameter machining.
Suitable for Small-Diameter Tools
Two flutes are commonly used in micro end mill designs where chip evacuation and controlled cutting engagement are important.
Controlled Cutting
The 2-flute geometry is suitable for precision applications where cutting conditions need to be carefully controlled to protect the small cutting edge.
Hardened Steel Performance
The HH(300) is designed primarily for high-hardness machining rather than general-purpose milling.
Up to 60 HRC
The stated application range covers hardened steel up to 60 HRC.
Mold Steel
The tool is suitable for precision machining of hardened mold and die components where small features and deep access are required.
High-Speed Machining
The TiSiN coating and ultra-fine carbide substrate are designed for demanding high-speed cutting conditions.
Dry and Semi-Dry Cutting
Dry and semi-dry machining are key application modes for the HH(300), although the appropriate cutting environment depends on the workpiece and machine setup.
Material Applications
| Workpiece Material | Application Focus |
| Hardened Steel ≤60 HRC | Micro grooves, cavities and fine features |
| Mold Steel | Small hardened mold components |
| Titanium Alloy | Precision difficult-material machining |
| Nickel-Based High-Temperature Alloy | Selected high-temperature alloy applications |
Actual performance depends on material grade, hardness, tool diameter, effective length, tool overhang, machine rigidity and cutting conditions.
HH(300) Tool Technology
0.3μm Ultra-Fine Carbide
The ultra-fine carbide substrate provides high hardness and wear resistance for demanding micro machining applications.
TiSiN PVD Coating
The TiSiN coating is designed for high-temperature cutting conditions and supports wear resistance during high-speed machining.
Specialized Geometry
The tool geometry is developed around the combined requirements of micro machining and extended reach rather than simply extending a standard square end mill.
High-Temperature Performance
The supplied product data specifies approximately 1200°C high-temperature resistance for the coating system. This refers to coating thermal performance and should not be interpreted as an actual cutting temperature.
Technical Specifications
| Parameter | Specification |
| Series | HH(300) |
| Tool Type | 2 Flute Micro Long Neck Carbide Square End Mill |
| Flute Count | 2 |
| End Type | Square |
| Design | Micro Long Neck |
| Carbide Substrate | 0.3μm Ultra-Fine Grain Carbide |
| Coating | TiSiN PVD |
| Hardened Steel Capability | Up to 60 HRC |
| Cutting Modes | High-Speed / Dry / Semi-Dry |
| Recommended Materials | Hardened Steel, Mold Steel, Titanium Alloy, Nickel-Based Alloys |
Key Dimensions
For this tool configuration, selection should consider:
How to Select the Right Configuration
Match the Tool Diameter to the Feature
Choose a cutting diameter that fits the narrowest feature while maintaining adequate tool strength.
Determine the Required Effective Length
Use the actual machining depth to determine the necessary reach. Avoid excessive tool extension.
Check Neck Clearance
The neck should be long enough to clear surrounding walls and shoulders without creating unnecessary unsupported length.
Confirm Workpiece Hardness
For hardened steel applications, confirm that the material falls within the 60 HRC range specified for the tool.
Control Tool Setup
Micro long-neck tools are sensitive to spindle runout, toolholding accuracy, vibration and overhang. A rigid setup is essential for stable cutting.
Cutting Conditions
The HH(300) is intended for high-speed, dry and semi-dry machining, but micro long-neck applications require carefully controlled cutting loads.
Recommended cutting data should be selected according to:
For application-specific recommendations, provide the tool diameter, material grade, hardness and machining depth.
Customization
Customized configurations are available for applications requiring specific dimensions or reach.
Custom Options
Frequently Asked Questions
What is the HH(300) 2 flute micro long neck end mill used for?
It is designed for small, deep and restricted machining features in hardened steel and mold steel, including micro grooves, recessed cavities and fine mold details.
Can the HH(300) machine hardened steel up to 60 HRC?
Yes. The HH(300) is designed for hardened steel applications up to 60 HRC with appropriate cutting conditions.
Why use a long neck micro end mill?
The combination of a small cutting diameter and extended neck provides access to narrow, deep and recessed features that standard micro end mills may not reach.
Is the HH(300) suitable for dry cutting?
Yes. High-speed, dry and semi-dry machining are key application modes for this tool.
Can the HH(300) machine titanium alloys and nickel-based alloys?
Yes. It can be used for selected titanium alloy and nickel-based high-temperature alloy applications under appropriate cutting conditions.
