Micro 100 GEC-250-4-020X 1/4in 4-Flute AlTiN Carbide End Mill

The Micro 100 GEC-250-4-020X is a new, USA-made solid carbide general-purpose end mill from Micro 100's Super Carbide line, featuring a 1/4 in (0.250 in) cutting diameter, 4 flutes, and a 0.020 in corner radius — decoding directly from the GEC (General End mill, Corner radius) – 250 (0.250 in dia) – 4 (4-flute) – 020 (0.020 in corner radius) – X (AlTiN coating) part number convention. The "X" suffix denotes Micro 100's AlTiN (Aluminum Titanium Nitride) coating, which provides a dark black finish visible in the photos, a surface hardness of approximately 3,300 HV, and a maximum working temperature of ~1,650 °F, making it well-suited for dry or minimal-lubrication machining of steels, stainless steels, cast iron, and titanium alloys. The 4-flute geometry with a 0.020 in corner radius (bullnose/corner-radius profile) provides increased flute rigidity and corner strength compared to a square-end mill, reducing chipping at the cutting edge in demanding side-milling, slotting, and profiling operations on CNC machining centers and mills with standard 1/4 in collets or ER-style toolholders.

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