ST-434-08
4 Flute Standard Length Super Tuffy Grade Carbide End Mill with Hone
0.25-in Dia 4-Flute End Mill, 0.75-in LOC, 0.25-in Shank, 2.5-in OAL


Super Tuffy grade carbide end mills for steel and high-temp alloys -- 3, 4, and 6 flute geometries with T-Process honed edges, corner breaks, and helix angles from 30 to 60 degrees, in inch (ST) and metric (MST).
- Super Tuffy carbide grade built for cast iron, steel, stainless steel, and super alloys
- ST-341 (3 flute stub) and ST-343 (3 flute standard): 40-degree helix with corner break and T-Process hone, rated high performance from slotting and ramping through finishing, 1/8" to 3/4"
- ST-360 (3 flute standard): 60-degree high-helix finisher for side milling, 1/8" to 3/4"
- ST-430 (4 flute standard, sharp edges) and ST-434 (4 flute standard, corner break with T-Process hone): 30-degree helix for side milling from roughing through finishing, 1/8" to 3/4" including half sizes on ST-430
- ST-630 (6 flute square end, 30-degree helix) and ST-646 (6 flute corner radius, 40-degree helix, honed radius): 3/8" to 1"; ST-646 available with coolant grooves (see guide page 13)
- Corner break sizes scale with diameter, from .003/.005 at 1/8" up to .011/.014 at 3/4"; ST-646 corner radii run .005/.007 to .012/.015
- Metric MST line mirrors the geometry: MST-341, MST-360, MST-430, MST-434 from 3 mm to 20 mm, and MST-646 from 10 mm to 20 mm
- Available uncoated or in TiN, TiCN, and AlTiN coatings
- Inch tolerances (ST-341/343): cutting diameter +.000/-.002 (1/8" to 1/4") or +.000/-.003 (5/16" to 3/4"), shank -.0001/-.0002, OAL +/-.060; ST-630/646 cutting diameter +.001/-.000; metric MST cutting diameter +.000/-.075 mm
- Need reach? See End Mill Modifications, guide page 14
From the RobbJack Applications Guide.
About this series
ST / MST Super Tuffy Grade Carbide End Mills
Honed-edge Super Tuffy tools for steel & high-temp alloys
The ST Series are Super Tuffy Grade carbide end mills with a T-Process honed edge, available in multiple geometries: ST-341 (3 flute, stub, 40 degree helix), ST-343 (3 flute, standard length), ST-360 (3 flute, 60 degree helix), ST-430 and ST-434 (4 flute, 30 degree helix), ST-630 and ST-646 (6 flute, 30/40 degree helix). Offered uncoated or with TiN, TiCN or AlTiN coatings, plus metric MST equivalents.
- 3, 4 and 6 flute configurations
- Square end and corner-radius / corner-break options
- T-Process honed edge
- Helix angles from 30 to 60 degrees depending on series
- Available uncoated or TiN, TiCN, AlTiN coated
- ST-646 available with coolant grooves
- Inch (ST) and metric (MST) sizes
Cast iron, steel, stainless steel and super alloys. Applications: slotting, side milling, helical interpolation, ramping, high-performance roughing, semi-finishing and finishing (dry, wet, cold air or spray mist), depending on series.
Headline spec
Super Tuffy Grade carbide with T-Process honed edge; uncoated or TiN/TiCN/AlTiN coated
Best for
- Steel and stainless steel
- Super alloys and high-temp materials
- Roughing through finishing
- Side milling and slotting
Specifications
US machining terms with ISO 13399 codes.
- Cutting DiameterDC
- 0.25″
- Diameter ToleranceDC tol
- 0.0010/0.0000
- Max Cutting DiameterDCX
- 0.251″
- Shank DiameterDMM
- 0.25″
- Length of Cut (LOC)APMX
- 0.75″
- Overall Length (OAL)OAL
- 2.5″
- Corner ChamferCHW
- 0.003″
- Chamfer AngleKCH
- 45°
- Number of FlutesNOF
- 4
- Helix AngleFHA
- 30°
- Helix HandFHH
- Right-hand
- Cut Direction
- Right-hand cut
- End Type
- Corner Break
- Center Cutting
- Yes — plunges
- Edge Prep
- T-Process honed edge
- Series
- ST-434 — 4 Flute Standard Length Super Tuffy Grade Carbide End Mill with Hone
Cuts these materials
Applications
See it run
Tolerances
| Type | Min | Max |
|---|---|---|
| Cutting Diameter | +0.001 | 0 |
| Length of Cut | +0.03 | 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) · $74.20 — 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 (4)
Uncoated
ST-434-08
$69.50
Available to order
ST-434-08-A
$74.20
Available to order
ST-434-08-C
$73.75
Available to order
ST-434-08-T
$72.60
Available to order
Starting at
$69.50
Performance guaranteed
More in the ST-434 series
Same series, different size — what changes from this tool is shown in red.
- ST-434-04$44.90Ø 0.125″LOC 0.5″OAL 1.5″4 FL
- ST-434-06$61.15Ø 0.1875″LOC 0.625″OAL 2″4 FL
- ST-434-10$93.00Ø 0.3125″LOC 0.8125″4 FLOAL 2.5″
- ST-434-12$111.90Ø 0.375″LOC 0.875″4 FLOAL 2.5″
- ST-434-16$152.80Ø 0.5″LOC 1″OAL 3″4 FL
- ST-434-20$318.40Ø 0.625″LOC 1.25″OAL 3.5″4 FL
- ST-434-24$456.35Ø 0.75″LOC 1.5″OAL 4″4 FL
- ST-341-04$35.70Ø 0.125″3 FLLOC 0.25″OAL 1.5″
- ST-341-06$53.80Ø 0.1875″3 FLLOC 0.375″OAL 2″
- ST-341-08$69.553 FLLOC 0.5″Ø 0.25″OAL 2.5″
- ST-341-10$74.50Ø 0.3125″3 FLLOC 0.5″OAL 2.5″
- ST-341-12$89.40Ø 0.375″3 FLLOC 0.625″OAL 2.5″