HH(300) 4 flute long neck carbide square end mill with 0.3μm ultra-fine carbide and TiSiN PVD coating for deep grooves, cavities and restricted machining in hardened steel up to 60 HRC.
The HH(300) 4 flute long neck end mill is designed for machining deep and restricted features in hardened steel and mold steel where a standard end mill cannot provide sufficient reach.
Its 0.3μm ultra-fine carbide substrate, TiSiN PVD coating and dedicated cutting geometry are designed for high-temperature and high-speed machining conditions. The long neck configuration provides additional clearance for deep grooves, recessed cavities and narrow mold features, while the tool is suitable for hardened steel up to 60 HRC.
High-speed, dry and semi-dry cutting are the primary application modes, with titanium alloys and nickel-based high-temperature alloys also suitable for selected applications.
Product Highlights
Deep Machining Applications
Deep Grooves
The long neck design provides the additional reach needed for deep grooves and slots where standard-length end mills may interfere with surrounding geometry.
Recessed Cavities
Suitable for recessed cavities where the cutting area is positioned below the surrounding workpiece surface.
Deep Ribs and Narrow Features
The extended neck provides clearance for narrow ribs, walls and other restricted mold features.
Mold and Die Machining
The HH(300) is suited to hardened mold and die components where high hardness and deep feature access need to be addressed together.
Deep Features in Hardened Steel
The combination of long-neck geometry and a hardened-steel-oriented coating system makes the tool suitable for deep machining applications up to 60 HRC under appropriate cutting conditions.
Long-neck square end mills are commonly used for narrow and deep machining, recessed features and mold applications. Industrial product ranges also identify effective length, neck dimensions and overall length as important selection factors.
Long Neck Design for Restricted Areas
The main advantage of the HH(300) long-neck configuration is not simply a longer tool. It is the additional clearance and reach behind the cutting section.
More Clearance
The reduced neck section helps the cutting edge reach recessed features without unnecessary interference between the tool body and the workpiece.
Deeper Access
The extended configuration is suited to features located deeper inside pockets and cavities.
Controlled Tool Reach
Effective length should be selected according to the actual machining depth. Excessive extension can reduce rigidity and increase vibration.
Better Access to Mold Features
The geometry is particularly relevant to deep ribs, narrow walls, pockets and recessed mold features.
Hardened Steel Performance
The HH(300) is designed around high-hardness machining rather than general-purpose steel cutting.
Up to 60 HRC
The stated application range covers hardened steel up to 60 HRC.
TiSiN for High-Temperature Cutting
The TiSiN PVD coating is intended for high-temperature machining and provides the hardness and thermal resistance required for demanding hardened-steel applications.
Suitable for Dry and Semi-Dry Cutting
The HH(300) is positioned for dry and semi-dry machining, reducing reliance on conventional coolant where the application and machine setup allow it.
Material Applications
| Workpiece Material | Recommended Application |
| Hardened Steel ≤60 HRC | Deep grooves, cavities and mold features |
| Mold Steel | Deep and restricted mold machining |
| Titanium Alloy | High-speed difficult-material machining |
| Nickel-Based High-Temperature Alloy | Selected high-temperature alloy applications |
Actual performance depends on workpiece 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 hardened-material applications.
TiSiN PVD Coating
The TiSiN coating is designed for high-temperature cutting conditions and supports wear resistance during high-speed machining.
Dedicated Tool Geometry
The HH(300) uses a specialized geometry developed for demanding machining rather than simply extending the body of a conventional square end mill.
Long Neck Structure
The neck configuration provides the additional clearance needed for deep and restricted features while keeping the cutting section focused on the actual machining area.
Technical Specifications
| Parameter | Specification |
| Series | HH(300) |
| Tool Type | 4 Flute Long Neck Carbide Square End Mill |
| Flute Count | 4 |
| End Type | Square |
| Design | 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 |
Critical Dimensions
For a long-neck end mill, diameter alone does not determine whether the tool is suitable.
Pay particular attention to:
How to Select the Right Configuration
Determine the Machining Depth
Measure the actual depth of the feature and select an effective length that reaches it without excessive extension.
Select the Cutting Diameter
Choose a diameter that fits the feature while maintaining adequate cutting strength.
Check Neck Clearance
The neck must provide enough clearance from surrounding walls, ribs and shoulders.
Minimize Tool Overhang
Longer unsupported length increases sensitivity to vibration and deflection, especially when machining hardened steel.
Match the Tool to the Material
Confirm that the workpiece hardness and material fall within the intended application range before selecting cutting conditions.
Cutting Conditions
The HH(300) supports high-speed, dry and semi-dry machining, but long-neck applications require more careful control of cutting load and tool rigidity.
Recommended cutting data should be selected according to:
For a suitable starting point, provide the tool diameter, machining depth, workpiece material and hardness.
Frequently Asked Questions
What is the HH(300) 4 flute long neck end mill used for?
The HH(300) is designed for deep grooves, recessed cavities, narrow mold features and other restricted machining areas in hardened and mold steels.
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 when appropriate cutting conditions are used.
Why use a long neck end mill for mold machining?
The long neck configuration provides additional clearance and reach for deep ribs, pockets, cavities and other features that are difficult to access with standard-length tools.
Is the HH(300) suitable for dry cutting?
Yes. High-speed, dry and semi-dry machining are key application modes for the HH(300).
Can the HH(300) machine titanium alloys and nickel-based alloys?
Yes. The tool can be used for selected titanium alloy and nickel-based high-temperature alloy applications under suitable cutting conditions.
Customization
Need a different reach, neck length or tool diameter?
JimmyTool can provide customized long-neck carbide end mills according to your machining requirements and technical drawings.
Custom Options
