- zane@samhotool.com
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SAMHO’s Corner Radius End Mills, also known as bull-nose mills, feature an innovative design that bridges the gap between square and ball nose end mills. By replacing the sharp, fragile corners of a square mill with a precision-ground radius, these tools significantly reduce stress concentration and the risk of chipping. Whether you are performing high-speed roughing in HRC65 mold steel or intricate contouring in graphite, SAMHO’s radiused cutters deliver exceptional stability, extended tool life, and a superior floor finish.
Increased Tool Life & Edge Strength: The rounded corner design evenly distributes cutting forces across a larger surface area. This prevents the premature “tip chipping” common in square end mills, allowing for more aggressive feed rates and ensuring stable performance during long-term, high-intensity machining.
Excellence in Hardened Alloys: SAMHO offers a comprehensive range of bull-nose cutters optimized for Steel, Stainless Steel, Titanium, Tungsten Copper, and Graphite. Our HRC65 series is specifically engineered to handle quenched mold steels with micron-level precision.
Thermal Stability & Friction Reduction: Our proprietary coatings act as a thermal shield, allowing for high-speed dry machining. For non-metallic materials, our CVD Diamond coating provides the ultimate abrasion resistance, maintaining sharp edges in the most “sandpaper-like” environments.
Reduced Chatter & Improved Finish: Featuring precisely engineered variable helix angles and rigid tool bodies, these mills mitigate harmonic vibration (chatter). This leads to smoother cuts in complex 3D pockets and reduces the need for secondary finishing operations.
Hardened Steel Series (HRC55/HRC65): The industry standard for mold and die components. Available in 4-Flute for high-efficiency milling and Long Neck versions for reaching deep into cavities.
Tungsten Copper Series: Specialized for W60-90 composites, providing the high-density strength needed to prevent material adhesion.
Graphite & Ceramic Series: Diamond-coated solutions optimized for the brittle, abrasive nature of graphite electrodes.
Copper & Aluminum Series: DLC-coated 2-flute and 4-flute designs that prevent “sticky” non-ferrous metals from welding to the tool edge.
| Parameter | Specification | User Benefit |
| Diameter Range | 0.2 mm – 20 mm | Suitable for applications ranging from micro-detail machining to bulk material removal |
| Radius Precision | ±0.005 mm to ±0.01 mm | Ensures consistent dimensions for complex and high-precision parts |
| Flute Count | 2 or 4 flutes | Provides a good balance between chip evacuation and tool rigidity |
| Helix Angle | 30° to 45° | Optimizes shearing action for improved surface finish and cutting performance |
| Shank Tolerance | h6 (ISO Standard) | Ensures compatibility with high-precision tool holders |
A: Sharp corners on square mills are the weakest point and prone to chipping. The Corner Radius design strengthens the edge, allowing for faster feed rates and much longer tool life. It also leaves a smoother “fillet” in the corners of pockets, which improves the structural integrity of the machined part.
A: A larger radius provides more edge strength and is better for heavy roughing. A smaller radius allows for more intricate detail and closer access to 90° corners. Choosing the largest possible radius for your part design will maximize tool longevity.
A: Use 2-flute (especially long-neck versions) for slotting or when machining softer, “gummy” materials like aluminum or copper where chip evacuation is critical. Use 4-flute for roughing and finishing harder steels, as the extra flutes provide more rigidity and a better surface finish.
A: Yes. Our TiAlN-coated carbide series is designed to resist the high heat generated by stainless steel and titanium. For the best results, use a consistent chip load and ensure your tool path avoids sudden shocks.
A: Long-neck tools allow you to reach deep into narrow pockets or around high walls. SAMHO’s long-neck series features a reinforced shank to prevent deflection and vibration, ensuring precision at the bottom of deep cavities.
A: For graphite, CVD Diamond is the only choice for high-volume work. It provides a hardness of 10,000 HV, resisting the extreme abrasion of graphite and allowing for stable machining for up to 18 hours.
A: The Arc Cut In (Helical Entry) prevents the tool from “slamming” into the material. This gradual entry protects the radiused edge from initial shock, ensuring a mark-free surface and preventing premature tool failure in hardened steel.
A: Tight shank tolerance ensures the tool is perfectly centered in the holder. Lower run-out means all flutes engage the material equally, leading to more uniform wear and much higher accuracy on the finished workpiece.
A: Absolutely. While ball nose mills are standard for 3D work, corner radius mills are often used for “rest milling” or rough contouring because they can remove more material faster while still providing a relatively smooth finish on flat or shallow sloped areas.
A: Standard HRC55/65 metric sizes are typically in stock. Custom radii (e.g., R0.3 or R0.7) or specialized neck lengths generally require 7-14 business days from technical approval.
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