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End MillMade in USA

ST-630-20

6 Flute Standard Length Super Tuffy Grade Carbide End Mill

0.625-in Dia 6-Flute End Mill, 1.25-in LOC, 0.625-in Shank, 3.5-in OAL

OrderingST-630-20·Uncoated·$373.65Change finish

6 Flute Standard Length Super Tuffy Grade Carbide End Mill — ST-630-20
Series photo — representative of the ST-630 family
OAL 3.5″Flute 1.25″Shank Ø0.625″Cutter Ø0.625″Square
Scaled drawing — true to this tool's dimensions (inch)
Speeds & FeedsDialed to this exact tool — free
Free CAD & DataSTEP 3DDXF 2DISO CSVCAM library
RobbJack ST Series Super Tuffy grade carbide end mill for steel and high-temp alloys with honed cutting edge

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
0.625″
Diameter ToleranceDC tol
0.0010/0.0000
Max Cutting DiameterDCX
0.626″
Shank DiameterDMM
0.625″
Length of Cut (LOC)APMX
1.25″
Overall Length (OAL)OAL
3.5″
Number of FlutesNOF
6
Helix AngleFHA
30°
Helix HandFHH
Right-hand
Cut Direction
Right-hand cut
End Type
Square End
Center Cutting
Yes — plunges
Series
ST-630 — 6 Flute Standard Length Super Tuffy Grade Carbide End Mill

Cuts these materials

Cast IronSteelStainless SteelSuperalloys (Inconel…)

Applications

Side MillingSemi-FinishingFinishingDryWetCold AirSpray Mist

See it run

Tolerances

TypeMinMax
Cutting Diameter+0.0010
Length of Cut+0.060
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.

Uncoated · your price$373.65

Part ST-630-20

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 ST-630-20 · Uncoated · $373.65

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Proven in the field

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Uncoated

$373.65

ST-630-20

Starting speeds & feeds for the ST-630-20

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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.

Starting speeds and feeds for RobbJack ST-630-20
MaterialOperationSFMRPMFeed (IPM)Chip load / toothDOC (in)WOC (in)
Gray IronFinishing5003,05673.3.00400.6250.0156
4140 SteelFinishing2201,3458.1.00100.6250.0156
303 StainlessFinishing5003,05627.5.00150.6250.0156

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 ST-630 series

Same series, different size — what changes from this tool is shown in red.