NS-402-32
4 Flute Variable Helix Std. Length Solid Carbide End Mill for Steels & Cast Iron
1-in Dia 4-Flute End Mill, 1.75-in LOC, 1-in Shank, 5-in OAL, 0.02-in Chamfer with Weldon Flats


4-flute variable-helix Tuffy grade end mills for cast iron and steels to 40 HRc — stub, standard, and long lengths, AlTiN coated, with optional flats for high-torque cuts.
- 4 flute, variable helix — the variable pitch damps harmonics for stable cuts in cast iron and steel up to 40 HRc hardness
- Three lengths per diameter: NS-401 stub, NS-402 standard, NS-403 long (e.g. 1/2": 3/4", 1-1/8", and 1-1/2" flute lengths)
- Inch sizes 3/16"–1"; metric MNS line runs 4–20 mm
- Every tool AlTiN (aluminum titanium nitride) coated, in flats (-FL) and no-flats versions — 'Slippage? Tool Holder — Add Flats!' for high-torque cuts
- Protective corner chamfer on every size, .008 to .02 by diameter (metric 0.2–0.5 mm)
- Guide engagement guidance: slot at 1 × diameter width and .5 × diameter depth; profile at .5 × diameter radial width and 1 × diameter axial depth
- Applications: slotting, side milling, helical interpolation, ramping, high-performance roughing, semi-finishing, and finishing — dry or wet
- Tolerances: NS cutting dia −.001/−.002, shank −.0001/−.0002, flute length +.060/−.000; MNS cutting dia −0.025/−0.050 mm, shank −0.002/−0.005 mm
From the RobbJack Applications Guide.
About this series
NS / MNS Tuffy Grade Carbide End Mills
Variable-helix 4-flute tools for titanium, steel & high-temp alloys
The NS Series (and metric MNS Series) are 4-flute Tuffy Grade carbide end mills with variable helix geometry, AlTiN coated, built for machining titanium, steel and high-temp alloys. Offered in stub (NS-401), standard (NS-402) and long (NS-403) lengths, with or without flats for high-torque cuts. Featured application: 6Al4V titanium flap track for airplane wings.
- 4 flute, square end
- Variable helix geometry
- AlTiN coated
- Available with flats for high-torque cuts (add -FL); flats eliminate tool-holder slippage
- Offered in stub, standard and long lengths
- Inch (NS) and metric (MNS) sizes
Cast iron, steel, and materials up to 40 HRc hardness; titanium and high-temp alloys. Applications: slotting, side milling, helical interpolation, ramping, high-performance roughing, semi-finishing and finishing (dry or wet).
Headline spec
4-flute variable-helix Tuffy Grade carbide, AlTiN coated
Best for
- Titanium machining (e.g. 6Al4V)
- Steel and high-temp alloys
- Slotting and profile milling
- High-performance roughing and finishing
Specifications
US machining terms with ISO 13399 codes.
- Cutting DiameterDC
- 1″
- Diameter ToleranceDC tol
- 0.0010/0.0000
- Max Cutting DiameterDCX
- 1.001″
- Shank DiameterDMM
- 1″
- Length of Cut (LOC)APMX
- 1.75″
- Overall Length (OAL)OAL
- 5″
- Corner ChamferCHW
- 0.02″
- Chamfer AngleKCH
- 45°
- Number of FlutesNOF
- 4
- Helix AngleFHA
- Variable
- Helix HandFHH
- Right-hand
- Cut Direction
- Right-hand cut
- End Type
- Chamfer
- Center Cutting
- Yes — plunges
- Shank Flats
- Available (-FL)
- Series
- NS-402 — 4 Flute Variable Helix Std. Length Solid Carbide End Mill for Steels & Cast Iron
Cuts these materials
Applications
See it run
Tolerances
| Type | Min | Max |
|---|---|---|
| Cutting Diameter | +0.001 | 0 |
| Length of Cut | +0.06 | 0 |
| Overall Length | +0.06 | -0.06 |
| Shank Diameter | -0.0001 | -0.0002 |
Made & shipped in the USA · lead time confirmed at order. Buy at retail or through your distributor.
Performance guaranteed. Run it against the tool you use today — if it doesn't beat it, we'll make it right.
Adds Aluminum Titanium Nitride (AlTiN) · $618.75 — our pick for your material. Choose another finish below.
Proven in the field
- $548,290saved per year drilling carbon-fiber aircraft
- $216,000saved per year trimming aircraft skins
- 1,000%metal-removal increase in Inconel 718 (SPS)
Finishes (2)
NS-402-32
$618.75
Available to order
NS-402-32-FL
$618.75
Available to order
Starting at
$618.75
Performance guaranteed
More in the NS-402 series
Same series, different size — what changes from this tool is shown in red.
- NS-402-06$65.75Ø 0.1875″LOC 0.625″OAL 2.5″4 FL
- NS-402-08$78.10Ø 0.25″LOC 0.75″OAL 2.5″4 FL
- NS-402-10$91.45Ø 0.3125″LOC 0.875″OAL 2.5″4 FL
- NS-402-12$111.55Ø 0.375″LOC 1″OAL 2.5″4 FL
- NS-402-16$164.10Ø 0.5″LOC 1.125″OAL 3″4 FL
- NS-402-20$254.90Ø 0.625″LOC 1.25″OAL 3.5″4 FL
- NS-402-24$386.25Ø 0.75″LOC 1.5″OAL 4″4 FL
- NS-401-06$58.05Ø 0.1875″LOC 0.375″OAL 2.5″4 FL
- NS-401-08$73.50Ø 0.25″LOC 0.5″OAL 2.5″4 FL
- NS-401-10$85.65Ø 0.3125″LOC 0.5″OAL 2.5″4 FL
- NS-401-12$104.10Ø 0.375″LOC 0.625″OAL 2.5″4 FL
- NS-401-16$154.55Ø 0.5″LOC 0.75″OAL 3″4 FL