HH(300) 4 flute carbide square end mill with 0.3μm ultra-fine carbide and TiSiN PVD coating, designed for high-speed dry and semi-dry milling of hardened and mold steels up to 60 HRC.
The HH300 4 flute end mill for hardened steel is designed for high-speed milling of hardened steels and mold steels where heat, wear and cutting-edge stability are critical.
A 0.3μm ultra-fine carbide substrate is combined with a high-performance TiSiN PVD coating to support machining conditions involving high cutting temperatures and hardened workpieces. The HH300 is suitable for hardened steel up to 60 HRC and is intended for high-speed, dry and semi-dry milling applications.
It can also be used for titanium alloys, nickel-based high-temperature alloys and other difficult-to-machine materials under appropriate conditions.
Product Highlights
Built for Hardened Steel Milling
Hardened steel places greater demands on an end mill than conventional steel because hardness and cutting temperature can accelerate edge wear and affect machining stability.
The HH300 is specifically positioned for this type of application.
Hardened Steel up to 60 HRC
The tool is designed for hardened steel applications up to 60 HRC, making it suitable for demanding mold, die and hardened-component machining.
Mold Steel Machining
The combination of fine-grain carbide, TiSiN coating and four-flute geometry makes the HH300 suitable for machining hardened mold and die steels.
High-Speed Cutting
The TiSiN coating is designed for high-temperature machining conditions, supporting high-speed cutting where conventional coatings may experience accelerated wear.
Dry and Semi-Dry Milling
The HH300 is particularly suited to dry and semi-dry cutting applications where reducing or eliminating coolant can improve process efficiency.
TiSiN-coated 4-flute end mills are commonly positioned for high-speed hardened-steel machining in the HRC52–60 range, with wear resistance being a major selling point.
Why TiSiN for Hardened Steel?
High-Temperature Stability
High-speed milling of hardened steel generates substantial cutting heat. The TiSiN coating is selected for demanding thermal conditions and high-temperature oxidation resistance.
High Hot Hardness
The coating maintains strong hardness characteristics at elevated temperatures, supporting cutting performance during high-speed machining.
Wear Resistance
The combination of TiSiN coating and 0.3μm ultra-fine carbide is intended to resist abrasive and thermal wear encountered in hardened-steel applications.
Suitable for Dry Cutting
Because the HH300 is designed for high-temperature machining conditions, it is particularly suitable for dry and semi-dry cutting where coolant use is limited.
TiSiN-coated carbide tools are widely used for hardened-steel machining because the coating is intended to retain wear resistance under elevated cutting temperatures. Comparable commercial products position TiSiN tools around HRC52–60 or higher and emphasize high-speed machining.
Where HH300 Fits
| Workpiece | Recommended Application |
| Hardened Steel ≤60 HRC | High-speed milling and precision machining |
| Mold Steel | Mold and die machining |
| Titanium Alloy | Difficult-material high-speed machining |
| Nickel-Based Superalloy | High-temperature alloy applications |
| Other Difficult Materials | Application dependent |
Final tool selection should consider workpiece grade, hardness, tool diameter, machine rigidity, engagement, overhang and cutting conditions.
0.3μm Ultra-Fine Carbide Substrate
The 0.3μm carbide substrate is one of the defining technical characteristics of the HH300.
The fine grain structure provides a combination of:
For hardened steel machining, substrate performance becomes especially important because the cutting edge is exposed to higher mechanical and thermal loads.
Four-Flute Square Geometry
The four-flute configuration gives the HH300 a balance between material removal efficiency and cutting-edge support.
Efficient Material Removal
Four cutting edges allow the tool to engage the workpiece efficiently during side milling, profiling and other milling operations.
Stable Cutting Edge
The multi-flute configuration supports stable cutting in hardened materials when the machine and toolholding system are sufficiently rigid.
Flat-Bottom Machining
The square end profile is suited to flat-bottom features, side walls, pockets and other applications where a flat cutting geometry is required.
Technical Specifications
| Parameter | Specification |
| Series | HH300 |
| Tool Type | 4 Flute Carbide Square End Mill |
| Flute Count | 4 |
| End Type | Square |
| 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 Superalloys |
Available Dimensions
Final tool selection should be based on the actual cutting geometry and machine setup.
Key dimensional parameters include:
Selecting HH300 for Hardened Steel
Check Workpiece Hardness
Confirm the actual material hardness before selecting the tool. HH300 is intended for hardened steel up to 60 HRC.
Consider the Machining Operation
The tool is suitable for applications such as:
Match Tool Diameter to Feature Size
Select the largest practical diameter that fits the machining geometry and maintains sufficient tool rigidity.
Check Machine Capability
High-speed hardened-steel machining requires sufficient spindle speed, toolholding accuracy and machine rigidity.
Choose Dry or Semi-Dry Cutting Carefully
Dry machining can increase thermal load on the cutting edge. Cutting parameters and tool engagement should therefore be matched to the material and machine setup.
Cutting Conditions for Hardened Steel
The HH300 is intended for high-speed machining, but cutting data must be matched to the exact tool diameter and workpiece hardness.
Recommended cutting information can include:
For hardened steel, recommended parameters should be selected according to:
Tool Diameter + Material Hardness + Machine Rigidity + Tool Overhang + Machining Operation
Dry & Semi-Dry Machining
The HH300 is particularly suited to dry and semi-dry machining applications.
Dry Cutting
Dry milling can eliminate coolant from the cutting process, but it also requires careful management of cutting heat and tool engagement.
Semi-Dry Cutting
When limited lubrication or cooling is available, cutting parameters should be adjusted to prevent excessive thermal loading.
When Coolant Is Required
Coolant-assisted machining may still be appropriate depending on the workpiece, cutting depth and machine configuration.
The goal is not to use dry cutting in every application, but to match the cutting environment to the tool coating, workpiece and machining conditions.
Difficult-Material Applications
Titanium Alloys
The HH300 can be used for selected titanium alloy applications where heat generation and tool wear require careful control.
Nickel-Based High-Temperature Alloys
The tool is also applicable to nickel-based high-temperature alloys under suitable cutting conditions.
Because these materials can generate substantial cutting temperatures and cutting forces, application-specific cutting data is recommended.
Custom Carbide End Mills
Need a specific diameter, shank configuration or tool geometry?
JimmyTool can manufacture customized carbide end mills according to technical drawings and machining requirements.
Custom Options
Frequently Asked Questions
What materials can the HH300 4 flute end mill machine?
The HH300 is designed primarily for hardened steel and mold steel up to 60 HRC. It can also be used for titanium alloys, nickel-based high-temperature alloys and other difficult materials under suitable conditions.
Is the HH300 suitable for 60 HRC hardened steel?
Yes. The recommended hardened-steel capability is up to 60 HRC with appropriate cutting parameters and machine conditions.
Why is TiSiN used on this end mill?
TiSiN is selected for high-temperature and wear-demanding machining applications, making it suitable for high-speed cutting of hardened materials.
Can the HH(300) be used for dry milling?
Yes. Dry and semi-dry cutting are key application modes for the HH(300).
Is the HH(300) suitable for mold steel?
Yes. The HH(300) is intended for hardened and mold steels, particularly where high-speed milling and wear resistance are important.
Can this tool machine titanium alloys?
Yes. Titanium alloys are among the difficult materials suitable for the HH(300) under appropriate cutting conditions.
Can it machine nickel-based superalloys?
Yes. The HH(300) can be used for selected nickel-based high-temperature alloy applications. Application-specific cutting data is recommended.
What hardness can the HH(300) handle?
The stated application range for hardened steel is up to 60 HRC.
Can JimmyTool customize the HH(300)?
Yes. JimmyTool can customize tool diameter, flute length, shank dimensions, geometry, coating and other specifications according to your requirements.
