The HRC65 4 flute end mill is an industrial-grade solid carbide milling tool engineered for high-efficiency side milling, slotting, and profiling on hardened steels up to HRC65. Featuring an ultra-fine 0.4 μm grain tungsten carbide substrate, this high-performance HRC65 4-flute flat end mill cutter delivers twice the tool life and metal removal rate compared to conventional two-flute tools.





Manufactured by Durable Mills, the HRC65 4 flute end mill series is precision-engineered for aggressive metal removal and superior surface finishing on extremely hard materials. Built on a premium micro-grain tungsten carbide substrate (0.4 μm grain size, 12% cobalt content, and HRA92.5–93 hardness), this solid carbide 4 flute flat milling cutter provides extreme structural rigidity, minimized vibration, and thermal stability in high-speed CNC machining centers.
| Property | Technical Value |
|---|---|
| Cobalt Content (Co) | 12% |
| Carbide Grain Size | 0.4 μm (Ultra-Fine Micro-Grain) |
| Hardness Rating | HRA 92.5 – 93.0 |
| Workpiece Hardness Range | Up to HRC65 |
| ISO | Workpiece Material | Depth of Cut (ap) | Width of Cut (ae) | Cutting Speed (Vc) | Feed Per Tooth (fz) |
|---|---|---|---|---|---|
| P | Carbon Steel / Alloy Steel (<35 HRC) | ap ≤ 1.5D | ae ≤ 0.1D | 120 m/min | 0.006D mm/z |
| P | Alloy Steel (35–48 HRC) | ap ≤ 1.5D | ae ≤ 0.1D | 80 m/min | 0.0035D mm/z |
| M | Stainless Steels | ap ≤ 1.5D | ae ≤ 0.1D | 100 m/min | 0.006D mm/z |
| K | Gray Cast Iron, Ductile Cast Iron (<32 HRC) | ap ≤ 1.5D | ae ≤ 0.1D | 120 m/min | 0.0055D mm/z |
| H | Alloy Steel, Hardened Steel (45–65 HRC) | ap ≤ 1.0D | ae ≤ 0.05D | 60–80 m/min | 0.003D mm/z |
| Model Type | Cutting Dia (D) mm | Flute Length (Lc) mm | Shank Dia (d) mm | Total Length (L) mm | Flutes |
|---|---|---|---|---|---|
| DM-3*8*3*50*4T | 3 | 8 | 3 | 50 | 4 |
| DM-3*12*3*75*4T | 3 | 12 | 3 | 75 | 4 |
| DM-3*15*3*100*4T | 3 | 15 | 3 | 100 | 4 |
| DM-1*3*4*50*4T | 1 | 3 | 4 | 50 | 4 |
| DM-1.5*4*4*50*4T | 1.5 | 4 | 4 | 50 | 4 |
| DM-2*5*4*50*4T | 2 | 5 | 4 | 50 | 4 |
| DM-2.5*7*4*50*4T | 2.5 | 7 | 4 | 50 | 4 |
| DM-3*8*4*50*4T | 3 | 8 | 4 | 50 | 4 |
| DM-3.5*10*4*50*4T | 3.5 | 10 | 4 | 50 | 4 |
| DM-4*10*4*50*4T | 4 | 10 | 4 | 50 | 4 |
| DM-4*16*4*75*4T | 4 | 16 | 4 | 75 | 4 |
| DM-4*20*4*100*4T | 4 | 20 | 4 | 100 | 4 |
| DM-5*13*5*50*4T | 5 | 13 | 5 | 50 | 4 |
| DM-5*20*5*75*4T | 5 | 20 | 5 | 75 | 4 |
| DM-5*25*5*100*4T | 5 | 25 | 5 | 100 | 4 |
| DM-1*3*6*50*4T | 1 | 3 | 6 | 50 | 4 |
| DM-1.5*4*6*50*4T | 1.5 | 4 | 6 | 50 | 4 |
| DM-2*5*6*50*4T | 2 | 5 | 6 | 50 | 4 |
| DM-2.5*7*6*50*4T | 2.5 | 7 | 6 | 50 | 4 |
| DM-3*8*6*50*4T | 3 | 8 | 6 | 50 | 4 |
| DM-3.5*10*6*50*4T | 3.5 | 10 | 6 | 50 | 4 |
| DM-4*10*6*50*4T | 4 | 10 | 6 | 50 | 4 |
| DM-4.5*12*6*50*4T | 4.5 | 12 | 6 | 50 | 4 |
| DM-5*13*6*50*4T | 5 | 13 | 6 | 50 | 4 |
| DM-6*15*6*50*4T | 6 | 15 | 6 | 50 | 4 |
| DM-6*25*6*75*4T | 6 | 25 | 6 | 75 | 4 |
| DM-6*30*6*100*4T | 6 | 30 | 6 | 100 | 4 |
| DM-6*40*6*150*4T | 6 | 40 | 6 | 150 | 4 |
| DM-7*18*8*60*4T | 7 | 18 | 8 | 60 | 4 |
| DM-8*20*8*60*4T | 8 | 20 | 8 | 60 | 4 |
| DM-8*28*8*75*4T | 8 | 28 | 8 | 75 | 4 |
| DM-8*35*8*100*4T | 8 | 35 | 8 | 100 | 4 |
| DM-8*50*8*150*4T | 8 | 50 | 8 | 150 | 4 |
| DM-9*23*10*75*4T | 9 | 23 | 10 | 75 | 4 |
| DM-10*25*10*75*4T | 10 | 25 | 10 | 75 | 4 |
| DM-10*40*10*100*4T | 10 | 40 | 10 | 100 | 4 |
It combines an ultra-fine 0.4 μm micro-grain carbide substrate with HRA 92.5–93 hardness and an advanced heat-shielding coating. This structure minimizes cutting resistance and resists notch wear even at elevated cutting temperatures up to 65HRC.
A 4-flute configuration offers significantly higher core strength and rigidity, making it ideal for side milling, profile finishing, and high-speed machining in hard metals where tool deflection must be prevented.
Yes. As a dedicated precision tooling manufacturer, Durable Mills provides complete OEM services, custom flute lengths, neck relief, and custom laser etching for wholesale clients.
You can contact our commercial sales team directly through our Contact Us page or email us at info@durablemills.com with your order requirements.