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End MillRouterMade in USA

P38-005138-1

4 Flute Solid Carbide Diamond Coated End Mill for Graphite & Composites

4 Flute Diamond Coated Square End Mill, 0.0938in Dia, 0.281in LOC, 0.125in Shank, 3.0in OAL

OrderingP38-005138-1·Diamond Coating (DCC)·$127.00

4 Flute Solid Carbide Diamond Coated End Mill for Graphite & Composites — P38-005138-1
Series photo — representative of the P38-4 family
OAL 3″Flute 0.281″Shank Ø0.125″Cutter Ø0.0938″Square
Scaled drawing — true to this tool's dimensions (inch)
Speeds & FeedsDialed to this exact tool — free
Free CAD & DataSTEP 3DDXF 2DISO CSVCAM library
P38 Lightning Series diamond coated end mills, square end and ball end with reach necks

Lightning Series thin-coat diamond end mills — extra edge sharpness at a graphite-friendly price

  • Lightning Series diamond coating (DCC) applied thinner than standard: reduced coating thickness increases edge sharpness and reduces cost — a cost-effective solution for machining graphite electrodes
  • 10–20x tool life over uncoated carbide from the CVD diamond coating
  • 2-flute micro sizes from 1/64" and 4-flute sizes from 1/32" to 1/2"; square end, ball end and corner radius (.005"–.062") end styles
  • Reach-style tools with a 30° typical neck taper for deep-cavity electrode work — e.g. 1/32" dia with up to 29/32" reach, 1/8" dia with up to 2" reach on a 3" OAL
  • Run dry, with cold air, or spray mist — no coolant required in graphite; also suited to composites, aluminum and plastics (pg 114)
  • Graphite speeds: soft 1000–2000 SFM, medium 750–1500 SFM, hard 500–1250 SFM, with roughing/finishing chipload-per-tooth tables by diameter (pg 116)
  • Standard tolerances: cutting dia +0.001/−0.001", shank h6, flute length ±0.060", OAL ±0.060"

From the RobbJack Applications Guide.

About this series

P38 Lightning Diamond Coated Series End Mills

A cost-effective diamond-coated solution for graphite electrodes.

The P38 Lightning Series offers a cost-effective solution for machining graphite electrodes. By reducing the coating thickness, edge sharpness is increased and cost is reduced. Available as 2-flute and 4-flute diamond-coated (DCC) end mills in ball-end, square-end, and corner-radius styles, with a typical 30 degree taper.

  • Diamond Coated (DCC)
  • Reduced coating thickness for increased edge sharpness and lower cost
  • 2-flute and 4-flute configurations
  • Ball-end, square-end, and corner-radius styles
  • 30 degree taper typical

Aluminum, Graphite, Composites, Plastics. Dry, Cold Air, or Spray Mist. Applications: conventional, ramping, high performance, 3-D, roughing, semi-finishing, finishing.

Headline spec

10-20X tool life over carbide

Best for

  • Machining graphite electrodes
  • Cost-effective diamond-coated milling of composites and plastics

Specifications

US machining terms with ISO 13399 codes.

Cutting DiameterDC
0.0938″
Shank DiameterDMM
0.125″
Length of Cut (LOC)APMX
0.281″
Overall Length (OAL)OAL
3″
Number of FlutesNOF
4
Shank Blend Angle
15°
End Type
Square End
Center Cutting
Yes — plunges
Series
P38-4 — 4 Flute Solid Carbide Diamond Coated End Mill for Graphite & Composites

Cuts these materials

Composites

Applications

High PerformanceHigh-SpeedMiniature

See it run

Tolerances

TypeMinMax
Length of Cut-0.06+0.06
Overall Length-0.06+0.06
Shank Diameter-0.0001-0.0003
Tool Diameter-0.001+0.001

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Each finish is a different part number and price.

DCC · your price$127.00

Part P38-005138-1

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 P38-005138-1 · Diamond Coating (DCC) · $127.00

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Download ISO 13399 data (.csv)

Proven in the field

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DCC

$127.00

P38-005138-1

Starting speeds & feeds for the P38-005138-1

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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 P38-005138-1
MaterialOperationSFMRPMFeed (IPM)Chip load / toothDOC (in)WOC (in)
HardwoodsFinishing29512,00057.6.00120.0938.0047

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 P38-4 series

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