S1-301-12
3 Flute Stub Length C-2 Grade Carbide End Mill
0.375-in Dia 3-Flute End Mill, 0.625-in LOC, 0.375-in Shank, 2.5-in OAL


2, 3 & 4 Flute C-2 Grade Carbide End Mills — stub length workhorses for aluminum and non-ferrous milling
- C-2 grade carbide end mills in stub length — 2 flute (S1-201), 3 flute (S1-301), and 4 flute (S1-401), all square end with 30° helix
- S1-201 inch sizes 1/16"–3/4" cutting diameter; metric MS1-201 2 flute in 2mm–20mm cutting diameters (38mm–92mm OAL)
- Applications: slotting, side milling, helical interpolation — from high performance roughing through semi-finishing and finishing, run dry, wet, cold air, or spray mist
- Materials: aluminum, copper, magnesium, plastics, composites, brass
- Uncoated or Diamond-Like Carbon (DLC) coated — every size in the series is offered in a -DLC version
- S1 tolerances: cutting dia. +.000/−.002 (1/16"–1/4") and +.000/−.003 (9/32"–3/4"); shank dia. −.0001/−.0002; flute length +.030/−.000 (1/16"–5/16") and +.060/−.000 (3/8"–3/4"); OAL ±.060
- MS1 tolerances: cutting dia. +.000/−.075mm; shank dia. −.002/−.005mm; flute length +0.500/+1.500mm; OAL ±10mm
- Available with wiper flats (guide p.17), coolant grooves (guide p.16), and 45° chamfer (guide p.17)
- S1-301/S1-401 available with shank flats to eliminate slippage in the tool holder (guide p.18)
From the RobbJack Applications Guide.



About this series
S1 C-2 Grade Carbide Stub Length End Mills
Stub-length C-2 carbide end mills in 2, 3, and 4 flute.
The S1 series is an inch-sized line of stub length C-2 grade solid carbide end mills offered in 2-flute (S1-201), 3-flute (S1-301), and 4-flute (S1-401) styles with a 30-degree helix and square end. Cutting diameters range from 1/16 inch up to 3/4 inch. Available with wiper flats, coolant grooves, and a 45-degree chamfer option; flats are available to eliminate slippage in the tool holder.
- C-2 grade carbide
- Stub length
- 30-degree helix
- Square end
- 2, 3, and 4 flute versions
- Available with wiper flats
- Available with coolant grooves
- Available with 45-degree chamfer
Aluminum, Copper, Magnesium, Plastics, Composites, Brass. Diamond-Like Carbon (DLC) coating available; dry, wet, cold air, or spray mist.
Headline spec
Cutting diameters 1/16 inch to 3/4 inch; C-2 grade carbide, stub length.
Best for
- Slotting
- Side Milling
- Helical Interpolation
- High Performance machining
- Roughing
- Semi-Finishing
- Finishing
Specifications
US machining terms with ISO 13399 codes.
- Cutting DiameterDC
- 0.375″
- Diameter ToleranceDC tol
- 0.0000/-0.0020
- Max Cutting DiameterDCX
- 0.375″
- Shank DiameterDMM
- 0.375″
- Length of Cut (LOC)APMX
- 0.625″
- Overall Length (OAL)OAL
- 2.5″
- Number of FlutesNOF
- 3
- Helix AngleFHA
- 30°
- Helix HandFHH
- Right-hand
- Cut Direction
- Right-hand cut
- End Type
- Square End
- Center Cutting
- Yes — plunges
- Series
- S1-301 — 3 Flute Stub Length C-2 Grade Carbide End Mill
Cuts these materials
Applications
See it run
Tolerances
| Type | Min | Max |
|---|---|---|
| Cutting Diameter | 0 | -0.003 |
| 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 Diamond-Like Carbon (DLC) · $77.05 — 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)
Uncoated
S1-301-12
$63.65
Available to order
S1-301-12-DLC
$77.05
Available to order
Starting at
$63.65
Performance guaranteed
More in the S1-301 series
Same series, different size — what changes from this tool is shown in red.
- S1-301-02$26.45Ø 0.0625″LOC 0.125″OAL 1.5″3 FL
- S1-301-03$26.35Ø 0.0937″LOC 0.1875″OAL 1.5″3 FL
- S1-301-04$25.85Ø 0.125″LOC 0.25″OAL 1.5″3 FL
- S1-301-06$31.45Ø 0.1875″LOC 0.375″OAL 2″3 FL
- S1-301-08$35.30Ø 0.25″LOC 0.5″OAL 2″3 FL
- S1-301-10$45.60Ø 0.3125″LOC 0.5″3 FLOAL 2.5″
- S1-301-14$86.30Ø 0.4375″OAL 2.75″3 FLLOC 0.625″
- S1-301-16$107.45Ø 0.5″OAL 3″3 FLLOC 0.625″
- S1-201-02$26.45Ø 0.0625″2 FLLOC 0.125″OAL 1.5″
- S1-201-03$26.35Ø 0.0937″2 FLLOC 0.1875″OAL 1.5″
- S1-201-04$25.85Ø 0.125″2 FLLOC 0.25″OAL 1.5″
- S1-201-06$31.45Ø 0.1875″2 FLLOC 0.375″OAL 2″