STR-401-08
4 Flute Stub Length Super Tuffy Grade Carbide Rougher
0.25-in Dia 4-Flute End Mill, 0.5-in LOC, 0.25-in Shank, 2.5-in OAL
OrderingSTR-401-08·Uncoated·$97.15Change finish
3 and 4 flute Super Tuffy grade carbide Ruffers for steel and stainless -- T-Process honed roughing tools in stub and standard lengths, inch (STR) and metric (MSTR).
- Dedicated roughing (Ruffer) geometry in Super Tuffy carbide for cast iron, steel, and stainless steel
- Four sub-series: STR-301 (3 flute stub), STR-303 (3 flute standard), STR-401 (4 flute stub), STR-404 (4 flute standard), all square end with corner break and 30-degree helix
- The whole STR Series comes with T-Process honed edges
- Inch sizes from 1/4" to 3/4" (stub) and 1/4" to 1" (standard); metric MSTR-301/303/401/404 from 6 mm to 20 mm
- Applications: slotting (3 flute stub), side milling, ramping, and roughing; run dry, wet, cold air, or spray mist
- Shank flats on 3/8", 1/2", 5/8", 3/4", and 1" sizes (asterisked sizes and all metric tools do not come with flats); order without flats by adding 'NF' to the tool number
- Roughing tolerances: cutting diameter -.003/-.007 (MSTR -.075/-.180 mm), shank diameter -.0001/-.0002, OAL +/-.060 (MSTR +/-10 mm)
- Available uncoated or in TiN, TiCN, and AlTiN coatings
From the RobbJack Applications Guide.
About this series
STR / MSTR Super Tuffy Grade Carbide Ruffers
Honed-edge roughers for steel & stainless
The STR Series are Super Tuffy Grade carbide ruffers (roughing end mills) with T-Process honed edges and a 30 degree helix, square end with corner break. Available in 3 flute (STR-301 stub, STR-303 standard) and 4 flute (STR-401 stub, STR-404 standard), uncoated or TiN, TiCN, AlTiN coated, plus metric MSTR equivalents. STR Series comes with T-Process honed edges; any tool can be ordered without flats by adding -NF.
- 3 flute and 4 flute roughing geometries
- Square end with corner break, 30 degree helix
- T-Process honed edge
- Available uncoated or TiN, TiCN, AlTiN coated
- Order without flats by adding -NF (metric tools do not have flats)
- Inch (STR) and metric (MSTR) sizes
Cast iron, steel and stainless steel. Applications: slotting, side milling, ramping and roughing (dry, wet, cold air or spray mist).
Headline spec
Super Tuffy Grade carbide ruffer, T-Process honed edge, 30 degree helix
Best for
- High-material-removal roughing in steel
- Stainless steel
- Slotting and side milling
Specifications
US machining terms with ISO 13399 codes.
- Cutting DiameterDC
- 0.25″
- Diameter ToleranceDC tol
- -0.0030/-0.0070
- Shank DiameterDMM
- 0.25″
- Length of Cut (LOC)APMX
- 0.5″
- Overall Length (OAL)OAL
- 2.5″
- Corner ChamferCHW
- 0.010/0.020
- Number of FlutesNOF
- 4
- Helix AngleFHA
- 30°
- Helix HandFHH
- Right-hand
- Cut Direction
- Right-hand cut
- End Type
- Square End
- Center Cutting
- Yes — plunges
- Series
- STR-401 — 4 Flute Stub Length Super Tuffy Grade Carbide Rougher
Cuts these materials
Applications
Features
See it run
Tolerances
| Type | Min | Max |
|---|---|---|
| Cutting Diameter | -0.003 | -0.007 |
| Length of Cut | +0.03 | 0 |
| Overall Length | +0.06 | -0.06 |
| Shank Diameter | -0.0001 | -0.0002 |
Choose the finish(4 options)
Compare →Each finish is a different part number and price.
Not sure? Compare tool coatings — or leave it uncoated, the most common choice for aluminum.
Part STR-401-08
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.
Uncoated
$97.15
STR-401-08
Starting speeds & feeds for the STR-401-08
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 | 500 | 7,640 | 97.8 | .00320 | .1250 | .2500 |
| 4140 Steel | Roughing — full slot | 220 | 3,362 | 10.8 | .00080 | .1250 | .2500 |
| 303 Stainless | Roughing — full slot | 500 | 7,640 | 36.7 | .00120 | .1250 | .2500 |
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 STR-401 series
Same series, different size — what changes from this tool is shown in red.
- STR-401-10$112.65Ø 0.3125″4 FLLOC 0.5″OAL 2.5″
- STR-401-12$140.15Ø 0.375″LOC 0.625″4 FLOAL 2.5″
- STR-401-14$214.60Ø 0.4375″LOC 0.625″OAL 2.75″4 FL
- STR-401-16$255.20Ø 0.5″LOC 0.625″OAL 3″4 FL
- STR-401-20$435.20Ø 0.625″LOC 0.875″OAL 3.5″4 FL
- STR-401-24$616.20Ø 0.75″LOC 1″OAL 4″4 FL
- STR-401-32$1005.85Ø 1″LOC 1.5″OAL 5″4 FL
- STR-301-08$94.103 FLØ 0.25″LOC 0.5″OAL 2.5″
- STR-301-10$112.65Ø 0.3125″3 FLLOC 0.5″OAL 2.5″
- STR-301-12$140.15Ø 0.375″3 FLLOC 0.625″OAL 2.5″
- STR-301-14$214.60Ø 0.4375″3 FLLOC 0.625″OAL 2.75″
- STR-301-16$255.20Ø 0.5″3 FLLOC 0.625″OAL 3″