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3/8 3 Flute 2 LOC Silverback ZrN Variable Helix Solid Carbide End Mill

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More Information
Mfg SKU #20464_GMA38FXL3ZrN
end mill categorySquare End
BrandGorilla Mill
Series NameSilverback
cutting diameter3/8
Shank Diameter3/8
flute length2
Overall Length4
Number of Flutes3
Materialmicrograin carbide
finish coatingZirconium Nitride
helix anglevariable helix
Flute Length TypeStandard
Chip Breaker FeatureNo
Single or Double Endsingle
To be used onAluminum, Brass, Bronze, Copper
center cuttingYes
end shapeSquare End
Shank Typeround shank
Coolant ThroughNo


Made in USAMade in USA


  • Variable Flute and Index | ZRN Coatings

    Variable flute and variable index. Engineered to repel aluminum. For roughing and finishing of non-ferrous materials, aluminum, copper, brass, plastic, etc. High velocity, high material removal rate. Center cutting.

  • Gorilla Mill 4 Flute in Action

    1.0" Diameter 0.750" Axial Engagement
    4140 PH 42.0" IPM
    Profiling 1910 RPM
    0.0250" Radial engagement  
  • ZRN

    Makes surfaces smoother, harder, and adds lubricity consequently increases tool performance and decreases friction

    Structure Nanohardness (GPa) Friction (fretting) Coefficient Thickness (um) Maximum Working Temp. Color
    Monolayer 28 0.4 2-4 550°C (1020°F) pale Y


The tool edge preparation process adds strength to the tool cutting edge, lengthens usable tool life, minimizes the propensity of the edge to chip, improves part quality and consistency, and enhances work piece surface finish.

With GMP Edge Prep, we have taken edge preparation to the next level, making it a science. Now the technology and equipment exists to overcome nearly all the current processing problems and to produce a tool that will yield optimum performance in any given operation or application.


Before GMP Edge Prep After GMP Edge Prep

Machining Method

Profiling Full Slotting Pocketing High-Velocity


  • Quality Assureance

    Our primary responsibility is to ensure the accuracy and consistency of product being manufactured. We have an array of quality inspection equipment including three Eurotech PG1000’s with up to 145x magnification, a Leica M205 C computerized photo microscope with up to 500x magnification, a Zoller pomSkpGo for edge prep measurements at 100x magnification and two Zoller Genius3 machines which are CNC controlled programmable inspection machines with 50X magnification.

  • Regrinds

    The vast majority of your tooling that Gorilla Mill or anyone else manufactures can be re-sharpened and recoated to “like new” condition on one of our state-of-the-art CNC tool and cutter grinders at a fraction of a new tool’s cost. At Gorilla Mill, our goal is to show cost savings while maintaining a high accuracy rate. Whether it’s Gorilla Mills,® or other variable end mills, standard end mills, Gorilla Drills or any other high performance drills, Gorilla Mill has over 40 years of knowledge and experience to help your bottom line.