51mm Long Drill Bits | McMaster-Carr

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.

Gold Oxide—Like black oxide, this finish adds wear resistance and reduces friction for improved chip flow. Because it’s less prone to flaking off, it offers better rust protection when bits aren't in use.

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	Pkg. Qty.		Pkg.
Jobbers' Length







				Gold Oxide

				1.65	0.065"	51	22.2	Round	1.7 mm	Split	1	000000000	00000


				1.65	0.065"	51	22.2	Round	1.7 mm	Split	10	000000000	00000
				1.7	0.0669"	51	22.2	Round	1.7 mm	Split	1	000000000	0000
				1.75	0.0689"	51	22.2	Round	1.8 mm	Split	1	000000000	0000
				1.8	0.0709"	51	22.2	Round	1.8 mm	Split	1	000000000	0000
				1.9	0.0748"	51	22.2	Round	1.9 mm	Split	1	000000000	0000
				2.0	0.0787"	51	22.2	Round	2 mm	Split	1	000000000	0000
				2.0	0.0787"	51	22.2	Round	2 mm	Split	10	000000000	00000




						Uncoated

						1.7	0.0669"	51	25.4	Round	1.7 mm	Standard	1	00000000	0000


						1.75	0.0689"	51	25.4	Round	1.8 mm	Standard	1	00000000	0000
						1.8	0.0709"	51	25.4	Round	1.8 mm	Standard	1	00000000	0000
						1.9	0.0748"	51	25.4	Round	1.9 mm	Standard	1	00000000	0000
						2.0	0.0787"	51	25.4	Round	2 mm	Standard	1	00000000	0000


						Short Length







										Titanium Nitride (TiN) Coated

										3.5	0.1378"	51	20.1	Round	3.5 mm	Split	1	0000000	0000

Chip-Clearing Cobalt Steel Drill Bits

Jobbers' Length

Parabolic Flute

Round Shank

Split

Avoid clogs and dissipate heat with cobalt bits that last at least twice as long as high-speed steel. The flutes clear chips to improve coolant flow and prevent damage to the bit and the hole. They also speed up drilling since you don't have to stop to clear the bit manually.

Jobbers' Length—These bits have the balance of rigidity and length needed for most applications.

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	Flute Type	Type	Size, mm	Drill Bit Point Type		Each
Jobbers' Length







				Uncoated

				1.75	0.0689"	51	25	Parabolic	Round	1.75	Split	00000000	00000


				1.8	0.0709"	51	25	Parabolic	Round	1.8	Split	00000000	0000
				1.9	0.0748"	51	25	Parabolic	Round	1.9	Split	00000000	0000
				1.95	0.0768"	51	25	Parabolic	Round	1.95	Split	00000000	0000
				2.0	0.0787"	51	25	Parabolic	Round	2	Split	0000000	0000

Left-Hand Cobalt Steel Drill Bits


Jobbers' Length Round Shank	Split

The flutes spiral in the opposite direction of other bits and stay sharp longer than high-speed steel. They’re primarily used to remove stripped screws. Choose a bit that’s slightly smaller than the diameter of the screw’s head. Set your power tool to rotate in reverse. Slowly drill in the center of the screw head, maintaining constant pressure. As the bit penetrates, it will catch onto the screw and reverse it out of the hole. If the screw is badly stripped, you might need to punch a starter hole. Also known as reverse-flute bits.

Jobbers' Length—These bits have the balance of rigidity and length needed for most applications.

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

					Shank				Each
	Drill Bit Size, mm	Decimal Size Equiv.	Overall Lg., mm	Max. Drilling Dp., mm	Type	Size	Drill Bit Point Type		1-9	10-Up
Jobbers' Length







				Uncoated

				2.0	0.0787"	51	25	Round	2 mm	Split	0000000	00000	00000