56mm Long Drill Bits | McMaster-Carr

Extended Length—Drill through panels and thick workpieces with our longest bits. Their length is good for creating deep holes but makes them less rigid than other bits. As a result, they are more prone to wobbling or breaking, especially when drilling hard materials.

Black Oxide—The dark finish increases wear resistance and reduces friction to improve chip flow, so these bits can last 50% longer than uncoated bits.

Titanium Nitride (TiN) Coated—Drill at higher speeds and last longer than uncoated and oxide-coated bits, especially on tough materials like hardened steel and nickel.

Uncoated—The most economical option, uncoated bits perform best when used on low-carbon steel and aluminum. Polished to reduce friction, they're also known as bright finish bits.

					Shank
	Drill Bit Size, mm	Decimal Size Equiv.	Overall Lg., mm	Max. Drilling Dp., mm	Type	Size	Drill Bit Point Type	Mfr.		Each
Short Length







				Titanium Nitride (TiN) Coated

				4.0	0.1575"	56	22.1	Round	4 mm	Split	Dormer Pramet	2979N19	00000


				4.2	0.1654"	56	22.1	Round	4.2 mm	Split	Dormer Pramet	2979N2	0000


				Extended Length







								Black Oxide

								1.0	0.0394"	56	33	Round	1 mm	Standard	Dormer Pramet	88455A111	0000




										Uncoated

										1.0	0.0394"	56	30.9	Round	1 mm	Standard	Dormer Pramet	3083A111	0000

Cobalt Steel Drill Bits

Short Length

Round Shank

Split

Tough and wear resistant, cobalt steel bits last at least twice as long as high-speed steel. They can also run up to 25% faster at higher temperatures without being damaged on hard materials, such as nickel.

Short Length—The most rigid bits for drilling the straightest holes.

Titanium Nitride (TiN) Coated—Drill at higher speeds and last longer than uncoated and oxide-coated bits, especially on tough materials like hardened steel and nickel.

Uncoated—Polished to eject chips, these are also known as bright finish bits.

					Shank
	Drill Bit Size, mm	Decimal Size Equiv.	Overall Lg., mm	Max. Drilling Dp., mm	Type	Size	Drill Bit Point Type	Mfr.		Each
Short Length







				Titanium Nitride (TiN) Coated

				4.0	0.1575"	56	14	Round	4 mm	Split	Chicago-Latrobe	2456N148	00000


				4.2	0.1654"	56	13.7	Round	4.2 mm	Split	Chicago-Latrobe	2456N149	0000




						Uncoated

						4.0	0.1575"	56	14	Round	4 mm	Split	Chicago-Latrobe	2456N121	0000


						4.2	0.1654"	56	13.7	Round	4.2 mm	Split	Chicago-Latrobe	2456N122	0000

Carbide-Tipped Drill Bits

Short Length

Round Shank

Standard

Performance similar to solid carbide but at a lower price point. Like carbide bits, these are stronger than cobalt and high-speed steel and maintain their sharp edges when drilling abrasive material. However, when drilling tough metals like iron and hardened steel, upgrade to carbide for longer life.

Short Length—The most rigid bits for drilling the straightest holes.

					Shank
	Drill Bit Size, mm	Decimal Size Equiv.	Overall Lg., mm	Max. Drilling Dp., mm	Type	Size	Drill Bit Point Type	Mfr.		Each
Short Length







				Uncoated

				4.5	0.1772"	56	13.5	Round	4.5 mm	Standard	Izar	28805A404	000000