4-Flute · nACo · R0.2mm · HRC65 · Standard Reach

4mm 4-Flute R0.2mm nACo Solid Carbide Corner Radius End Millfor HRC65 Hardened Steel

Name: 4mm 4-Flute R0.2mm nACo Corner Radius End Mill for HRC65
Brand: Solid Carbide Direct
SKU: SCD-CREM-NACO-4F-D4-R02-L15
Price: 12.37 USD
Availability: InStock

nACo (nano-AlCrN composite) corner radius end mills deliver the highest performance tier for hard milling in die steel, tool steel, and hardened components up to HRC65. The corner radius geometry is especially critical at high hardness — it eliminates the notching failure mode that destroys sharp-corner tools in hardened steel. Combined with nACo's 3,800 HV hardness and 1,100°C oxidation resistance, this tool enables dry semi-finish and finish passes in H13, P20, D2, and S7 mould steel directly after heat treatment.

R0.2mmD1 4mmL2 15mmD2 4mmOAL 75mm4 FlutesnACoHRC65Standard ReachMOQ 1 pc

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Reference price

$12.37

Ref. factory price (USD)

Based on rod stock cost as of 2026-03-31. Final quotation may differ.

4mm 4F R0.2mm nACo

L2 15mm · D2 4mm · OAL 75mm

Standard Reach · HRC65

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✓ Factory direct pricing

✓ MOQ 1 piece, ships 1–5 days

✓ Custom radius in 0.1mm increments

Full Dimensions

Technical Specifications

Corner Radius	0.2 mm
Cutter Diameter (D1 h7)	4 mm
Flute Length (L2)	15 mm
Shank Diameter (D2 h6)	4 mm
Overall Length (L1)	75 mm
Number of Flutes	4
End Geometry	Corner Radius (Bull Nose)
Coating	nACo Nano-AlCrN composite
Max Material Hardness	HRC65
Reach Category	Standard (L1/D1 = 18.8×)
Helix Angle	30°–35°
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 · R0.2mm

Corner R

0.2mm

D1 h7

4mm

15mm

D2 h6

4mm

75mm

Reach

Standard

R0.2mm Corner Geometry

Micro edge protection — minimal corner rounding for near-sharp corner features

▸Virtually sharp corner appearance while eliminating micro-chipping
▸Ideal where fillet radius tolerance is ± 0.05mm
▸Extends tool life vs true sharp-corner tools by 30–50%
▸Suitable for precision mould parting surfaces and embossed lettering

Radius Selection Tip: R0.2mm is the tightest corner radius standard. In HRC65 steel, the R0.2mm arc is small enough to appear visually sharp but prevents the notching failure that destroys zero-radius tools. Use identical step-over and depth parameters as you would for a square end mill.

ø4mm Applications

4mm nACo — Where This Tool Fits

▸Mould cavity pocket semi-finishing
▸Precision aerospace part profiling
▸Hydraulic manifold pocket corners
▸Small fixture and jig features

Machining Tip: ø4mm with corner radius provides the best size-to-stiffness ratio for die and mould work. In HRC65 steel, the corner radius allows 3–5×D axial depth without the micro-chipping that limits sharp-corner tools. Ideal for continuous shoulder milling passes.

Coating Performance

nACo on Corner Radius Geometry

▸nACo hardness > 3,800 HV — critical for corner edge stability in HRC65 steel
▸Oxidation to 1,100°C — supports dry cutting in deep die pockets
▸Corner radius + nACo eliminates notching failure common in hard milling
▸Enables direct finish after heat treatment — skip grinding on mould steel

ISO HISO PnACo corner radius end mill HRC654 flute bull nose end mill hardened steelcorner radius carbide end mill hard millingradius end mill die steel HRC65

Same Diameter & Radius, Different Reach