0.4mm End Mills | McMaster-Carr

With a mill diameter less than _1/8" or 3 mm, these end mills are great for precise, detailed work such as in electronics, mold making, and medical-device manufacturing. They have a square end for milling square-bottomed slots, pockets, and edges. All are center cutting, allowing plunge cuts into a surface.

Made of solid carbide, these end mills are harder, stronger, and more wear resistant than high-speed steel and cobalt steel for the longest life and best finish. Their extreme hardness means they are brittle, so a highly rigid setup, such as a CNC machine, is necessary to prevent the end mill from breaking.

End mills with fewer flutes provide better chip clearance for high-volume, high-speed plunge, slotting, and roughing cuts; end mills with more flutes provide a finer finish and operate with less vibration when run at high speeds.

Uncoated Carbide—Use uncoated end mills for general purpose milling and short production runs. They stay sharper than coated end mills when used on soft materials like aluminum, leaving a better finish.

	Mill, mm
	Dia.	Dia. Tolerance	Shank Dia., mm	Lg. of Cut, mm	Overall Lg., mm	Flute Spacing	Helix Angle	For Use On	End Mill Type	Cut Style	Mfr.		Each
Uncoated Carbide







				2 Flutes

				0.4	-0.0127 to 0.0127	3	1.2	38	Equal	30°	Aluminum, Brass, Bronze, Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium, Tool Steel	Center Cutting	Square	Microcut	5000N19	000000

Long-Reach Carbide Ball End Mills for Mold Making


Ball Cut Style	2 Flutes

These end mills have an extended neck with a reduced diameter that prevents them from rubbing against your workpiece when deep milling. Also known as runner cutters, they cut channels with precise angles and dimensions, reducing the need for additional finishing. They have a ball end for milling rounded slots, slopes, and contours. All are center cutting, allowing plunge cuts into a surface.

Made of solid carbide, these end mills are harder, stronger, and more wear resistant than high-speed steel and cobalt steel for the longest life and best finish on hard material. Their extreme hardness means they are brittle, so a highly rigid setup, such as a CNC machine, is necessary to prevent the end mill from breaking.

Uncoated Carbide—Use uncoated end mills for general purpose milling and short production runs. They will stay sharper than coated end mills and leave a better finish on soft materials like aluminum.

Aluminum Titanium Nitride (AlTiN)-Coated Carbide—Use aluminum titanium nitride (AlTiN)-coated end mills for demanding, high-speed jobs in hard material as well as for longer production runs. The coating reduces friction and vibration as they’re used, making them more wear resistant than uncoated end mills. They dissipate heat better than other end mills, especially at high speeds. At high temperatures, the coating creates a layer of aluminum oxide that transfers heat to the chips, keeping the tool cool, even when used without lubrication.

	Mill, mm			Neck, mm
	Dia.	Dia. Tolerance	Shank Dia., mm	Dia.	Lg.	Lg. of Cut, mm	Overall Lg., mm	Flute Spacing	Helix Angle	For Use On	End Mill Type	Cut Style	Mfr.		Each
Uncoated Carbide







				2 Flutes

				0.4	0.0000 to 0.0991	4	0.38	7.6	0.4	50	Equal	30°	Aluminum, Brass, Bronze, Copper, Fiberglass, Hardened Steel, Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium, Tool Steel	Center Cutting	Ball	Titan USA	8086N13	0000000


				Aluminum Titanium Nitride (AlTiN)-Coated Carbide







								2 Flutes

								0.4	0.0000 to 0.0991	4	0.38	7.6	0.4	50	Equal	30°	Hardened Steel, Iron, Nickel, Stainless Steel, Steel, Titanium, Tool Steel	Center Cutting	Ball	Titan USA	8086N24	000000


								0.4	0.0000 to 0.0991	6	0.35	0.7	0.5	57	Equal	30°	Hardened Steel, Iron, Nickel, Stainless Steel, Steel, Titanium, Tool Steel	Center Cutting	Ball	Titan USA	8086N25	000000

Carbide Square End Mills for Carbon Fiber, Fiberglass, and Graphite

2 Flutes

A diamond or diamondlike coating on these end mills makes them good for machining abrasive material, such as carbon fiber, fiberglass, and graphite. Made of solid carbide, these end mills are harder, stronger, and more wear resistant than high-speed steel and cobalt steel for the longest life and best finish on hard material. Their extreme hardness means they are brittle, so a highly rigid setup, such as a CNC machine, is necessary to prevent the end mill from breaking. They have a square end for milling square-bottomed slots, pockets, and edges. All are center cutting, allowing plunge cuts into a surface.

Diamond-Coated Carbide—Diamond-coated end mills are good for long production runs. They run twice as fast as other carbide end mills and last up to 30 times longer.

	Mill, mm
	Dia.	Dia. Tolerance	Shank Dia., mm	Lg. of Cut, mm	Overall Lg., mm	Flute Spacing	Helix Angle	For Use On	End Mill Type	Cut Style	Mfr.		Each
Diamond-Coated Carbide







				2 Flutes

				0.4	-0.025 to 0	3	0.6	40	Equal	30°	Carbon Fiber, Fiberglass, Graphite	Center Cutting	Square	RobbJack	3725A303	0000000

Carbide Ball End Mills for Carbon Fiber, Fiberglass, and Graphite


Ball Cut Style	2 Flutes

These end mills have a diamond or diamondlike coating for machining abrasive material, such as carbon fiber, fiberglass, and graphite. Made of solid carbide, they are harder, stronger, and more wear resistant than high-speed steel and cobalt steel for the longest life and best finish. Their extreme hardness means they are brittle, so a highly rigid setup, such as a CNC machine, is necessary to prevent the end mill from breaking. They have a ball end for milling rounded slots, slopes, and contours. All are center cutting, allowing plunge cuts into a surface.

Diamond-Coated Carbide—Diamond-coated end mills are good for long production runs. They run twice as fast as other carbide end mills and last up to 30 times longer.

	Mill, mm
	Dia.	Dia. Tolerance	Shank Dia., mm	Lg. of Cut, mm	Overall Lg., mm	Flute Spacing	Helix Angle	For Use On	End Mill Type	Cut Style	Mfr.		Each
Diamond-Coated Carbide







				2 Flutes

				0.4	0.385 to 0.4000	4	0.8	40	Equal	30°	Carbon Fiber, Fiberglass, Graphite	Center Cutting	Ball	Seco	3725A13	0000000

Carbide Ball End Mills for Tool Steel, Hardened Steel, and Iron


Ball Cut Style

Flutes have a low helix angle to provide the cutting forces required for difficult-to-machine material, such as hardened steel and iron. Made of solid carbide, these end mills are harder, stronger, and more wear resistant than high-speed steel and cobalt steel for the longest life and best finish on hard material. Their extreme hardness means they are brittle, so a highly rigid setup, such as a CNC machine, is necessary to prevent the end mill from breaking. They have a ball end for milling rounded slots, slopes, and contours. All are center cutting, allowing plunge cuts into a surface.

Aluminum Chromium Nitride (AlCrN)-Coated Carbide—An aluminum titanium nitride (AlTiN) or aluminum chromium nitride (AlCrN) coating allows them to dissipate heat better than other end mills, especially at high speeds. At high temperatures, the coating creates a layer of aluminum oxide that transfers heat to the chips, keeping the tool cool, even when used without lubrication. This makes these good for aggressive machining while roughing or making interrupted cuts.

	Mill, mm											For Maximum Hardness Rockwell C63
	Dia.	Dia. Tolerance	Shank Dia., mm	Lg. of Cut, mm	Overall Lg., mm	Flute Spacing	Helix Angle	For Use On	End Mill Type	Cut Style	Mfr.		Each
Aluminum Chromium Nitride (AlCrN)-Coated Carbide







				2 Flutes

				0.4	-0.01 to 0.005	4	0.3	45	Equal	30°	Hardened Steel, Iron, Tool Steel	Center Cutting	Ball	Sandvik Coromant	8942A113	0000000

Cubic Boron Nitride Ball End Mills for Tool Steel and Hardened Steel


Ball Cut Style

Make finishing cuts in tool steel and hardened steel with these cubic boron nitride (CBN) end mills. Harder than carbide end mills, they’re better for making small, precise cuts and last more than five times as long. And while they’re not as hard as diamond end mills, they dissipate heat much better. These end mills have a 0° helix angle for increased rigidity, helping to prevent chipping and ensuring more precise cuts. Deep chip pockets remove small chips for greater precision and to prevent surface roughening.

Because they’re brittle, these end mills require a highly rigid setup such as a CNC machine to prevent them from breaking. It’s also recommended that they’re used with oil coolant.

Mill, mm			Neck, mm										For Maximum Hardness Rockwell C70
Dia.	Dia. Tolerance	Shank Dia., mm	Dia.	Lg.	Lg. of Cut, mm	Overall Lg., mm	Flute Spacing	Helix Angle	For Use On	End Mill Type	Cut Style	Mfr.		Each







			2 Flutes

			0.4	-0.006 to 0.006	4	0.37	0.2	0.3	50	Equal	0°	Hardened Steel, Tool Steel	Center Cutting	Ball	Mikron Tool	7977N15	0000000