31 ga 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	Decimal Size Equiv.	Overall Lg.	Max. Drilling Dp.	Type	Size	Drill Bit Point Type		Each
Jobbers' Length







				Black Oxide

				31 Ga.	0.12"	2 3/4"	1.44"	Round	0.12"	Split	2901A205	00000




						Titanium Nitride (TiN) Coated

						31 Ga.	0.12"	2 3/4"	1.44"	Round	0.12"	Split	29045A754	0000




								Uncoated

								31 Ga.	0.12"	2 3/4"	1.44"	Round	0.12"	Standard	30585A44	0000


								Short Length







												Black Oxide

												31 Ga.	0.12"	1 7/8"	0.69"	Round	0.12"	Split	2896A544	0000




														Titanium Nitride (TiN) Coated

														31 Ga.	0.12"	1 7/8"	0.88"	Round	0.12"	Split	3584A211	0000




																Uncoated

																31 Ga.	0.12"	1 7/8"	0.88"	Round	0.12"	Standard	8947A184	0000


																Extended Length







																				Black Oxide

																				31 Ga.	0.12"	5 1/8"	2.57"	Round	0.12"	Standard	3096A344	00000

Cobalt Steel Drill Bits


Jobbers' Length Round Shank	Short Length Round Shank

Extended 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.

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

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	Decimal Size Equiv.	Overall Lg.	Max. Drilling Dp.	Type	Size	Drill Bit Point Type		Each
Jobbers' Length







				Titanium Nitride (TiN) Coated

				31 Ga.	0.12"	2 3/4"	1.63"	Round	0.12"	Split	27995A644	00000




						Uncoated

						31 Ga.	0.12"	2 3/4"	1.44"	Round	0.12"	Split	3033A244	0000


						Short Length







										Titanium Nitride (TiN) Coated

										31 Ga.	0.12"	1 7/8"	0.48"	Round	0.12"	Split	28765A943	0000




												Uncoated

												31 Ga.	0.12"	1 7/8"	0.7"	Round	0.12"	Split	28765A81	0000


												Extended Length







																Uncoated

																31 Ga.	0.12"	5 1/8"	2.5"	Round	0.12"	Split	88555A71	00000

Drill Bit Size Gauges

For Wire

Gauge

Measure drill bit sizes with these gauges.

For Taps—Drills/taps gauges include a tap size conversion chart.

For System of Measurement	For Use With	For Drill Bit Size	Wd.	Ht.	Thk.	Material	Color	Mounting Hole Dia.		Each
Wire Gauge	Drills/Taps	60 Ga., 59 Ga., 58 Ga., 57 Ga., 56 Ga., 55 Ga., 54 Ga., 53 Ga., 52 Ga., 51 Ga., 50 Ga., 49 Ga., 48 Ga., 47 Ga., 46 Ga., 45 Ga., 44 Ga., 43 Ga., 42 Ga., 41 Ga., 40 Ga., 39 Ga., 38 Ga., 37 Ga., 36 Ga., 35 Ga., 34 Ga., 33 Ga., 32 Ga., 31 Ga., 30 Ga., 29 Ga., 28 Ga., 27 Ga., 26 Ga., 25 Ga., 24 Ga., 23 Ga., 22 Ga., 21 Ga., 20 Ga., 19 Ga., 18 Ga., 17 Ga., 16 Ga., 15 Ga., 14 Ga., 13 Ga., 12 Ga., 11 Ga., 10 Ga., 9 Ga., 8 Ga., 7 Ga., 6 Ga., 5 Ga., 4 Ga., 3 Ga., 2 Ga., 1 Ga.	2 1/2"	6 1/2"	5/64"	Steel	Silver	1/8"	8986A68	000000

Carbide Drill Bits

Jobbers' Length

Round Shank

The hardest and most wear-resistant drill bits you can buy. Carbide bits stay sharp at high temperatures and faster speeds for the best performance on hard and difficult-to-machine materials. They last 10 to 20 times longer than their closest alternative, cobalt steel. Carbide can be brittle, however, so these bits require a rigid machine tool holder to prevent breakage and should not be used in hand drilling applications.

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

Titanium Nitride (TiN) Coated—Drill at higher speeds and last longer than uncoated bits, especially on materials like hardened steel, iron, and stainless steel.

Uncoated—Excellent for a range of materials but won't last as long as coated bits.

					Shank
	Drill Bit Size	Decimal Size Equiv.	Overall Lg.	Max. Drilling Dp.	Type	Size	Drill Bit Point Type		Each
Jobbers' Length







				Titanium Nitride (TiN) Coated

				31 Ga.	0.12"	2 1/4"	1"	Round	0.12"	Four Facet	8825A432	000000




						Uncoated

						31 Ga.	0.12"	2 1/4"	1"	Round	0.12"	Four Facet	2860A44	00000

Expanded-Shank Carbide Drill Bits


Jobbers' Length	Standard

The shank fits the same-size chuck as standard drill bits, so you can spend less time setting up. Because these bits make very small holes, they’re often used for drilling circuit boards. Carbide bits are the the hardest and most wear resistant. They stay sharp at high temperatures and faster speeds for the best performance on hard and difficult-to-machine materials. Carbide can be brittle, however, so bits require a rigid machine tool holder to prevent breakage and should not be used in hand drilling applications.

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

Titanium Nitride (TiN) Coated—Drill at higher speeds and last longer than uncoated bits, especially on materials like hardened steel, iron, and stainless steel.

Titanium Aluminum Nitride (TiAlN) Coated—No drill bits last longer. These are the best for high-speed, high-temperature drilling of very hard and abrasive materials, including titanium and fiberglass.

Uncoated—Excellent for a range of materials but won't last as long as coated bits.

					Shank
	Drill Bit Size	Decimal Size Equiv.	Overall Lg.	Max. Drilling Dp.	Type	Size	Drill Bit Point Type		Each
Jobbers' Length







				Titanium Nitride (TiN) Coated

				31 Ga.	0.12"	1 1/2"	0.3"	Expanded Round	1/8"	Four Facet	6415N167	000000




						Titanium Aluminum Nitride (TiAlN) Coated

						31 Ga.	0.12"	1 1/2"	0.36"	Expanded Round	1/8"	Standard	2598N159	00000




								Uncoated

								31 Ga.	0.12"	1 1/2"	0.3"	Expanded Round	1/8"	Standard	2841A31	0000

Carbide Drill Bits for Hardened Steel


Short Length Round Shank	Split

The hardest and most wear-resistant bits with the longest life. Straight flutes withstand the heavy pressure needed to penetrate hardened steel. These bits cut more aggressively and resist stress better than spiral-flute bits. Carbide stays sharp at high temperatures and faster speeds for the best performance on hard and difficult-to-machine materials. It can be brittle, however, so these bits require a rigid machine tool holder to prevent breakage and should not be used in hand drilling applications.

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

Titanium Nitride (TiN) Coated—Drill at higher speeds and last longer than uncoated bits, especially on materials like hardened steel, iron, and stainless steel.

Uncoated—Excellent for a range of materials but won't last as long as coated bits.

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







				Titanium Nitride (TiN) Coated

				31 Ga.	0.12"	2 1/4"	0.5"	Round	0.12"	Split	8882A65	000000




						Uncoated

						31 Ga.	0.12"	2 1/4"	0.5"	Round	0.12"	Four Facet	8944A7	00000

Helical Threaded Insert Assortments with Installation Tools

Repair damaged threads or create new ones. These convenient assortments include helical inserts, an installation tool for each thread size, a drill bit, and a tap. The inserts are also known as Heli-Coil inserts.

Pronged—The prong attaches to an installation tool for precise control as you drive inserts in. Remove the prong with a punch or break-off tool before inserting a screw.

18-8 Stainless Steel—The choice for wet and outdoor environments, these inserts resist rust and mild chemicals.

	Drill Bit Size	For Max. Hole Dia.		Each
Pronged







	18-8 Stainless Steel

	36	4-40 Thread × 0.112" Installed Lg. (12 Each) 4-40 Thread × 0.168" Installed Lg. (12 Each) 4-40 Thread × 0.224" Installed Lg. (12 Each) Drill Bit Installation Tool Prong Break-Off Tool Through-Hole Tap	Coarse	31 Ga.	0.120"	91732A901	000000


	288	1-64 Thread × 0.11" Installed Lg. (24 Inserts and 24 Screw-Locking Inserts) 2-56 Thread × 0.129" Installed Lg. (24 Inserts and 24 Screw-Locking Inserts) 3-48 Thread × 0.148" Installed Lg. (24 Inserts and 24 Screw-Locking Inserts) 4-40 Thread × 0.168" Installed Lg. (24 Inserts and 24 Screw-Locking Inserts) 6-32 Thread × 0.207" Installed Lg. (24 Inserts and 24 Screw-Locking Inserts) 8-32 Thread × 0.246" Installed Lg. (24 Inserts and 24 Screw-Locking Inserts) Drill Bits Installation Tools Through-Hole Taps	Coarse	5/64" 3/32" 36 Ga. 31 Ga. 26 Ga. 17 Ga.	0.078" 0.094" 0.107" 0.120" 0.147" 0.173"	90285A134	000000

Short-Flute High-Speed Steel Drill Bits

Extended Length

Round Shank

Split

The rigidity of short-length bits without sacrificing reach. The shallow drilling depth makes these less likely to wobble than other bits of the same length, so they stay centered and drill straighter. High-speed steel is good for general purpose drilling in most metals.

Extended Length—Drill through panels and thick workpieces with our longest bits.

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.

					Shank
	Drill Bit Size	Decimal Size Equiv.	Overall Lg.	Max. Drilling Dp.	Type	Size	Drill Bit Point Type		Each
Extended Length







				Black Oxide

				31 Ga.	0.12"	6"	1.44"	Round	0.12"	Split	3161A44	00000


				31 Ga.	0.12"	12"	1.44"	Round	0.12"	Split	3158A144	00000

High-Speed Steel Drill Bits for Plastic

The precision-ground, 60° point penetrates gradually to prevent cracking and chipping. It also reduces heat that can deform the material. Use these bits for drilling into acrylic, laminate, and other plastics. They're made of wear-resistant high-speed steel.

Jobbers' Length About Jobbers' Length

					Shank
	Drill Bit Size	Decimal Size Equiv.	Overall Lg.	Max. Drilling Dp.	Type	Size	Point Angle	Drill Bit Point Type		Each
Uncoated



		31 Ga.	0.12"	2 3/4"	1"	Round	0.12"	60°	Standard	27465A344	00000

Short-Flute Cobalt Steel Drill Bits


Jobbers' Length Round Shank	Extended Length Round Shank	Split

These bits combine the toughness and wear resistance of cobalt with short flutes for rigidity. The shallow drilling depth makes them less likely to wobble than other bits of the same length, so they stay centered and drill straighter. Cobalt lasts at least twice as long as high-speed steel. It can also run up to 25% faster at higher temperatures without damaging the bit on hard materials such as nickel.

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

Extended Length—Drill through panels and thick workpieces with our longest bits.

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.

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

					Shank
	Drill Bit Size	Decimal Size Equiv.	Overall Lg.	Max. Drilling Dp.	Type	Size	Drill Bit Point Type		Each
Jobbers' Length







				Black Oxide

				31 Ga.	0.12"	2 3/4"	0.7"	Round	0.12"	Split	3146A206	00000


				Extended Length







								Uncoated

								31 Ga.	0.12"	6"	1.38"	Round	0.12"	Split	8952A182	0000

Carbide Drill Bits for Carbon Fiber, Fiberglass, and Graphite

Jobbers' Length

Cut clean holes in abrasive material without fraying or delaminating the surface. Made of carbide, these bits resist wear to retain a sharp edge, even after after hundreds of cuts.

					Shank
	Drill Bit Size	Decimal Size Equiv.	Overall Lg.	Max. Drilling Dp.	Type	Size	Point Angle	Drill Bit Point Type	Bit Style		Each
Jobbers' Length







				Uncoated

				31 Ga.	0.12"	2 1/4"	1"	Round	0.12"	140°	Brad	Fluted	2828A868	000000

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	Decimal Size Equiv.	Overall Lg.	Max. Drilling Dp.	Flute Type	Type	Size	Drill Bit Point Type		Each
Jobbers' Length







				Uncoated

				31 Ga.	0.12"	2 1/2"	1.41"	Parabolic	Round	0.12"	Split	28555A54	00000

Smooth-Finish Carbide Drill Bits


Jobbers' Length Round Shank	Split

With more cutting edges than other drill bits, these cut continuously and consistently for a smoother finish. They also stay centered to produce holes that are straighter and more accurate. However, since there’s less space between the cutting edges, they don’t clear chips as quickly. Made of carbide, these are the hardest and most wear-resistant drill bits you can buy. They stay sharp at high temperatures and faster speeds for the best performance on hard and difficult-to-machine materials. Carbide can be brittle, however, so these bits require a rigid machine tool holder to prevent breakage and should not be used in hand drilling applications.

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

Uncoated—Excellent for a range of materials but won't last as long as coated bits.

					Shank
	Drill Bit Size	Decimal Size Equiv.	Overall Lg.	Max. Drilling Dp.	Type	Size	Drill Bit Point Type		Each
Jobbers' Length







				Uncoated

				31 Ga.	0.12"	2 1/4"	1"	Round	0.12"	Split	3171A89	000000

Carbide-Tipped Drill Bits

Jobbers' Length

Round Shank


Standard	Split

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.

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

					Shank
	Drill Bit Size	Decimal Size Equiv.	Overall Lg.	Max. Drilling Dp.	Type	Size	Drill Bit Point Type		Each
Jobbers' Length







				Uncoated

				31 Ga.	0.12"	2 3/4"	1.35"	Round	0.12"	Standard	2940A434	000000


				31 Ga.	0.12"	2 3/4"	1.4"	Round	0.12"	Split	31575A444	00000

Left-Hand High-Speed Steel Drill Bits


Jobbers' Length Round Shank	Standard

With flutes that spiral in the opposite direction of other bits, these are 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. High-speed steel is the versatile choice for drilling most metals.

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

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				Each
	Drill Bit Size	Decimal Size Equiv.	Overall Lg.	Max. Drilling Dp.	Type	Size	Drill Bit Point Type		1-11	12-Up
Jobbers' Length







				Uncoated

				31 Ga.	0.12"	2 3/4"	1.38"	Round	0.12"	Standard	3024A254	00000	00000

Chip-Clearing High-Speed Steel Drill Bits


Jobbers' Length High Helix Flute Round Shank	Jobbers' Length Parabolic Flute Round Shank

Standard

Split

With flutes that lift chips out of the hole, you don't have to stop drilling to clear these bits manually. They improve coolant flow to dissipate heat and prevent clogs that can damage the bit and ruin the hole. High-speed steel is good for general purpose drilling in most metals.

High Helix Flute—Less aggressive than parabolic flutes for cleaner cuts in soft metals.

Parabolic Flute—A U-shaped groove on the flutes cuts faster and clears chips more quickly than high-helix bits, so these are better for drilling deeper holes.

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

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	Decimal Size Equiv.	Overall Lg.	Max. Drilling Dp.	Flute Type	Type	Size	Drill Bit Point Type		Each
Jobbers' Length







				Black Oxide

				31 Ga.	0.12"	2 3/4"	1.4"	Parabolic	Round	0.12"	Split	27575A54	00000




						Titanium Nitride (TiN) Coated

						31 Ga.	0.12"	2 3/4"	1.4"	Parabolic	Round	0.12"	Split	29925A976	0000




								Uncoated

								31 Ga.	0.12"	2 3/4"	1.4"	Parabolic	Round	0.12"	Split	2761A241	0000


								31 Ga.	0.12"	2 3/4"	1.44"	High Helix	Round	0.12"	Standard	2912A205	0000

Short-Flute Carbide-Tipped Drill Bits

Extended Length

Round Shank

Split

Our strongest short-flute bits, these have a carbide tip that stays sharp when drilling abrasive materials, such as titanium. The shallow drilling depth makes them less likely to wobble than other bits of the same length, so they stay centered and drill straighter.

Extended Length—Drill through panels and thick workpieces with our longest bits.

					Shank
	Drill Bit Size	Decimal Size Equiv.	Overall Lg.	Max. Drilling Dp.	Type	Size	Drill Bit Point Type		Each
Extended Length







				Uncoated

				31 Ga.	0.12"	12"	1.33"	Round	0.12"	Split	2854A454	000000

M2 High-Speed Tool Steel Rod Sets

Supplied in a metal index case with fold-out panels, these rods, also known as drill blanks, have an undersized diameter for machining your own jobbers'-length drill bits. They are hardened for increased abrasion and impact resistance. M2 tool steel offers a nice balance of wear resistance and machinability. It has a high molybdenum content, which allows it to maintain sharp cutting edges even at elevated temperatures.

Includes	No. of Pieces	Dia. Tolerance	Mechanical Finish		Each
Sizes 1-60 and a metal index case	60	-0.0002" to 0"	Precision Ground	2952A6	0000000

Helical Threaded Inserts with Installation Tools

Drill Bit, Installation Tool

and Through-Hole Tap

Quickly restore stripped threads—these inserts come with through-hole taps and installation tools. The tough coils on these inserts expand once installed to anchor in a tapped hole.

Pronged—The prong attaches to an installation tool for precise control as you drive inserts in. Remove the prong with a punch or break-off tool before inserting a screw.

18-8 Stainless Steel—The choice for wet and outdoor environments, these inserts resist rust and mild chemicals.

	For Max. Hole Dia.	No. of Inserts Included	Includes		Each
Pronged







	18-8 Stainless Steel

	4-40	0.112"	31 Ga.	0.120"	10	Drill Bit Installation Tool Through-Hole Tap	98356A114	0000000


	4-40	0.168"	31 Ga.	0.120"	10	Drill Bit Installation Tool Through-Hole Tap	91732A899	00000
	4-40	0.224"	31 Ga.	0.120"	10	Drill Bit Installation Tool Through-Hole Tap	91732A430	00000
	4-40	0.280"	31 Ga.	0.120"	10	Drill Bit Installation Tool Through-Hole Tap	98356A115	000000
	4-40	0.336"	31 Ga.	0.120"	10	Drill Bit Installation Tool Through-Hole Tap	98356A116	000000

Depth-Limiting Drill Stops

Image of ProductInUse. Front orientation. Drill Stops.

Ensure identical hole depths every time. Position the collar on your bit and tighten the set screw.

	For Drill Bit Size Decimal Equiv.	Overall Lg.	OD	Hex Key Size for Set Screw	Material		Each
For Wire Gauge Drill Bits



	31 Ga.	0.1200"	1/2"	3/8"	3/32"	Steel	8865A131	00000

Undersized Hardened Multipurpose M2 High-Speed Tool Steel Rods

These rods, also known as drill blanks, have an undersized diameter for machining your own drill bits. They're hardened for increased abrasion and impact resistance. M2 tool steel offers a nice balance of wear resistance and machinability. It has a high molybdenum content, which allows it to maintain sharp cutting edges even at elevated temperatures.

Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.

Dia.	Dia. Tolerance	Drill Bit Size	Lg.	Yield Strength	Hardness	Mechanical Finish		Each
0.12"	-0.0002" to 0"	31 Ga.	2 3/4"	Not Rated	Rockwell C60 (Extra Hard)	Precision Ground	3009A244	00000

Tight-Tolerance Water-Hardening W1 Tool Steel Rods

Ready for turning in your lathe, these rods are precision ground and held to strict diameter and straightness tolerances. Also known as drill rod. With far less alloy content than other tool steel, W1 is the most machinable we offer. These rods are often used to make hammers, files, and reamers—tools that don't require the dimensional stability of A2 or O1. These rods are also decarb-free, which means any surface flaws created during the manufacturing process have been removed. This makes them even more machinable and leads to better results from heat treating or finishing. Heat treat the surface for extra wear resistance. Or, quench this steel in water to boost its hardness and strength, giving it a sharper, more durable edge for small tools.

Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.

Dia.	Dia. Tolerance	Drill Bit Size	Fabrication	Heat Treatment	Yield Strength, psi	Mechanical Finish	Hardness	Max. Hardness After Heat Treatment	Specs. Met		3 ft. Long	6 ft. Long
0.12"	0.000" to 0.0003"	31 Ga.	Hot Rolled	Annealed	50,000	Precision Ground	Rockwell B95 (Medium)	Rockwell C65	ASTM A686	8890K145	00000	00000