4-Flute · nACo · HRC65 · Standard Reach
4mm 4-Flute nACo Solid Carbide Square End Millfor HRC65 Hardened Steel
nACo (nano-AlCrN composite) coating represents the highest-performance tier in the square end mill range. With a coating hardness exceeding 3,800 HV and an oxidation temperature of 1,100°C, nACo enables dry cutting in hardened steel up to HRC65 — direct competition with CBN tooling at a fraction of the cost. 4-flute geometry with tight tolerance on corner radius (< 0.01mm) delivers consistent surface quality in die and mould hardened cavities, hardened shaft features, and precision gear blanks. Requires rigid fixturing and maximum 0.005mm spindle runout.
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Reference price
$9.00
Ref. factory price (USD)
Based on rod stock cost as of 2026-03-31. Final quotation may differ.
4mm 4F nACo Square EM
L2 10mm · D2 4mm · OAL 50mm
Standard Reach · HRC65
✓ Factory direct pricing
✓ MOQ 1 piece, ships 1–5 days
✓ Custom OAL and helix available
Full Dimensions
Technical Specifications
| Cutter Diameter (D1 h7) | 4 mm |
| Flute Length (L2) | 10 mm |
| Shank Diameter (D2 h6) | 4 mm |
| Overall Length (L1) | 50 mm |
| Number of Flutes | 4 |
| Coating | nACo Nano-AlCrN composite |
| Max Material Hardness | HRC65 |
| Reach Category | Standard (L1/D1 = 12.5×) |
| Helix Angle | 30°–45° (application dependent) |
| End Geometry | Square (flat end) |
| Substrate | K10/K20 Ultra-Fine Grain Carbide |
| Shank Tolerance | h6 |
| MOQ | 1 piece |
| Lead Time (standard) | 1–5 business days |
| Lead Time (custom) | 5–15 business days |
nACo · 4 Flute · HRC65
Where This Tool Excels
4mm nACo 4F — Recommended Applications
- ▸Die and mould fine detail features
- ▸Aerospace precision component profiling
- ▸Small hydraulic manifold pocketing
- ▸Electronic enclosure and heat-sink machining
Coating Performance
nACo — Why It Works
- ▸Coating hardness > 3,800 HV — harder than TiN or TiAlN
- ▸Oxidation resistance to 1,100°C — enables dry cutting in hardened steel
- ▸Direct competitor to CBN at lower tooling cost
- ▸Ideal for die/mould cavities and hardened shaft features
Same Diameter, Different Reach
ø4mm nACo · 4 Flute · HRC65 — Other Flute Lengths
Same Size, Different Coating
ø4mm / L2 10mm — Other Variants
Order 4mm 4-Flute nACo Today
Factory direct. MOQ 1 piece. Pricing confirmed within 4 hours.