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
OrderingNS-402-32·Aluminum Titanium Nitride (AlTiN)·$849.05Change finish


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 |
Choose the finish(2 options)
Compare →Each finish is a different part number and price.
Part NS-402-32
Made & shipped in the USA · lead time confirmed at order. Test this tool in your spindle at retail, or get it through your RobbJack distributor.
Performance guaranteed. Run it against the tool you use today — if it doesn't beat it, we'll make it right.
Adds NS-402-32 · Aluminum Titanium Nitride (AlTiN) · $849.05
AlTiN
$849.05
NS-402-32
Starting speeds & feeds for the NS-402-32
Dial in for your machine →RobbJack's tested starting numbers for this exact tool, from the same engine and the same default machine as the calculator: a 12,000 RPM / 400 IPM / 30 HP machining center, rigid setup, full-depth cut. A faster or smaller spindle changes the RPM and feed — enter yours in the calculator and it re-governs every number.
| Material | Operation | SFM | RPM | Feed (IPM) | Chip load / tooth | DOC (in) | WOC (in) |
|---|---|---|---|---|---|---|---|
| Gray Iron | Roughing — full slot | 525 | 2,006 | 36.1 | .00450 | .6648 | 1.0000 |
| Gray Iron | Finishing | 525 | 2,006 | 36.1 | .00450 | 1.5000 | .0250 |
| 4140 Steel | Roughing — full slot | 400 | 1,528 | 17.1 | .00280 | .7000 | 1.0000 |
| 4140 Steel | Finishing | 400 | 1,528 | 17.1 | .00280 | 1.5000 | .0250 |
| P20 (30-40hrc) Tool Steel | Roughing — full slot | 415 | 1,585 | 17.8 | .00280 | .7000 | 1.0000 |
| P20 (30-40hrc) Tool Steel | Finishing | 415 | 1,585 | 17.8 | .00280 | 1.5000 | .0250 |
Read before you run
Recommendations are computed starting points based on typical conditions — not guarantees of performance, tool life, or fitness for your application. Machining involves inherent risk: you are solely responsible for safe operation, for verifying every parameter against your machine, spindle, toolholding, workholding, and guarding limits, and for proving all parameters on a test cut before production. RobbJack Corporation assumes no liability for tool breakage, machine damage, scrapped parts, production loss, or personal injury arising from use of these recommendations. By using this calculator you accept RobbJack's Terms & Conditions.
More in the NS-402 series
Same series, different size — what changes from this tool is shown in red.
- NS-402-06$74.95Ø 0.1875″LOC 0.625″OAL 2.5″4 FL
- NS-402-08$106.15Ø 0.25″LOC 0.75″OAL 2.5″4 FL
- NS-402-10$110.25Ø 0.3125″LOC 0.875″OAL 2.5″4 FL
- NS-402-12$134.45Ø 0.375″LOC 1″OAL 2.5″4 FL
- NS-402-16$204.60Ø 0.5″LOC 1.125″OAL 3″4 FL
- NS-402-20$328.40Ø 0.625″LOC 1.25″OAL 3.5″4 FL
- NS-402-24$495.85Ø 0.75″LOC 1.5″OAL 4″4 FL
- NS-401-06$67.25Ø 0.1875″LOC 0.375″OAL 2.5″4 FL
- NS-401-08$101.55Ø 0.25″LOC 0.5″OAL 2.5″4 FL
- NS-401-10$104.45Ø 0.3125″LOC 0.5″OAL 2.5″4 FL
- NS-401-12$127.00Ø 0.375″LOC 0.625″OAL 2.5″4 FL
- NS-401-16$195.05Ø 0.5″LOC 0.75″OAL 3″4 FL