4 mm Reamers | McMaster-Carr

Straight Flute—The most common flute style, these reamers are suitable for a wide range of applications, but not recommended for holes with a keyway or other breaks in the surface.

High-Speed Steel—Durable and wear resistant, these are good for general purpose reaming in most materials.

Cobalt Steel—With better heat and wear resistance than high-speed steel, these reamers run up to 25% faster, last longer, and perform better on hard materials, such as cast iron, hardened steel, titanium, and stainless steel.

Carbide—For the highest level of accuracy when cutting hard materials, these are our hardest, strongest, and most wear-resistant reamers. They're used on materials such as iron, hardened steel, steel alloys, and plastic. Their hardness means they are brittle, so a highly rigid setup, such as a CNC machine, is necessary to prevent the reamer from breaking.

			Lg., mm
	Reamer Dia.	Material	Flute	Overall	No. of Flutes	Cutting Dia. Tolerance, mm	For Use On		Each
Straight Flute







				Metric

				4.0000 mm	High-Speed Steel	25.4	101.6	6	0 to 0.005	Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel	0000000	000000


				4.0000 mm	Cobalt Steel	25.4	101.6	6	0 to 0.005	Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel, Tool Steel, Hardened Steel	0000000	00000
				4.0000 mm	Carbide	19.1	63.5	4	0 to 0.005	Aluminum, Brass, Bronze, Fiberglass, Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium, Tool Steel, Hardened Steel	00000000	00000

Square Shank

Spiral Flute

Turn these reamers by hand with an adjustable wrench or straight-handle tap wrench (sold separately).

Spiral Flute—Since these reamers clear chips better than straight flutes, they leave holes with a smoother finish. They're better for holes with breaks in the surface, such as a keyway, because they cut continuously across the breaks instead of moving in and out.

High-Speed Steel—Durable and wear resistant, these are good for general purpose reaming in most materials.

Left-Hand Spiral—These reamers push chips downward as they cut, so they're often used in through holes.

				Lg., mm
	Reamer Dia.	Material	Square Shank Size, mm	Flute	Overall	No. of Flutes	Spiral Direction	Cutting Dia. Tolerance, mm	Specs. Met	For Use On		Each
Spiral Flute







				Metric

				4.0000 mm	High-Speed Steel	3	38	76	6	Left Hand	0.005 to 0.01	DIN 206	Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel	0000000	000000

Reamer Sets

Keep a variety of reamer sizes on hand for finishing holes.

Round Shank

These reamers fit in the chuck of drill presses, turret lathes, and other machine and power tools, making them the most common shank type.

Straight Flute—The most common flute style, these reamers are suitable for a wide range of applications, but not recommended for holes with a keyway or other breaks in the surface.

High-Speed Steel—Durable and wear resistant, these are good for general purpose reaming in most materials.

	Container Type	For Use On		Each
Straight Flute







	Metric

	1-7 mm (Increments of 0.5 mm)	13	High-Speed Steel	Wood Case	Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel	0000000	0000000


	1-13 mm (Increments of 0.5 mm)	25	High-Speed Steel	Metal Case	Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel	0000000	000000