4-Flute · nACo · R0.3mm · HRC65 · Standard Reach

8mm 4-Flute R0.3mm nACo Solid Carbide Corner Radius End Millfor HRC65 Hardened Steel

Name: 8mm 4-Flute R0.3mm nACo Corner Radius End Mill for HRC65
Brand: Solid Carbide Direct
SKU: SCD-CREM-NACO-4F-D8-R03-L20
Price: 34.28 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.

R0.3mmD1 8mmL2 20mmD2 8mmOAL 60mm4 FlutesnACoHRC65Standard ReachMOQ 1 pc

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Reference price

$34.28

Ref. factory price (USD)

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

8mm 4F R0.3mm nACo

L2 20mm · D2 8mm · OAL 60mm

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	0.3 mm
Cutter Diameter (D1 h7)	8 mm
Flute Length (L2)	20 mm
Shank Diameter (D2 h6)	8 mm
Overall Length (L1)	60 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 = 7.5×)
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 · R0.3mm

Corner R

0.3mm

D1 h7

8mm

20mm

D2 h6

8mm

60mm

Reach

Standard

R0.3mm Corner Geometry

Light edge protection for tight-tolerance pocket corners

▸Prevents corner micro-fracture in interrupted cuts
▸Works within tight pocket radius tolerances (e.g. R0.3 ± 0.05mm)
▸Preferred radius for watch and instrument component pockets
▸Usable on features requiring clean corner breaks in cast iron

Radius Selection Tip: R0.3mm suits precision pockets where a larger radius would violate the design fillet spec. In HRC65 steel, this radius absorbs chip impact without generating visible corner burrs. Verify pocket design tolerance before specifying — most CAD models default to R0.5mm.

ø8mm Applications

8mm nACo — Where This Tool Fits

▸Automotive component shoulder milling
▸Pump body and valve pocket features
▸Gearbox cover profiling
▸Large mould runner channel machining

Machining Tip: ø8mm is the production sweet spot for corner radius end mills. In HRC65 steel, radial engagement can be 30–50% of D for profiling, with DOC up to 1×D for semi-finish passes. The corner radius reduces chatter significantly at this diameter.

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 ø8mm Diameter, Other Radii