1/8" Keys | McMaster-Carr

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66 Products

Woodruff Keys


	Side View

Woodruff keys work well near shaft shoulders, where a standard open keyway would create too much stress. They are also often used on tapered shafts. These keys have a rounded shape that makes them easy to remove when parts need to be taken apart frequently, such as for maintenance or prototyping. Because they're usually shorter than standard machine keys, they work best in light duty applications. Use them to connect gears and other components to shafts. Also known as half moon keys.

1018-1045 Carbon Steel and 8630 Alloy Steel—Steel keys offer good strength.

316 Stainless Steel—316 stainless steel keys have excellent corrosion resistance, but aren't as strong as steel keys. They may be mildly magnetic.

Inch—Inch keys conform to ASME B17.2 standards for dimensions and tolerances.

						Tolerance
	Woodruff Key No.	Wd.	For Keyway Dia.	Ht.	Lg.	Wd.	Ht.	Specs. Met	System of Measurement	Pkg. Qty.		Pkg.
1018-1045 Carbon Steel



		3	1/8"	1/2"	0.194"	0.491"	0.000" to 0.001"	-0.006" to 0.000"	ASME B17.2	Inch	100	000000000	000000


		5	1/8"	5/8"	0.24"	0.612"	0.000" to 0.001"	-0.006" to 0.000"	ASME B17.2	Inch	100	000000000	00000
		7	1/8"	3/4"	0.303"	0.74"	0.000" to 0.001"	-0.006" to 0.000"	ASME B17.2	Inch	100	000000000	00000
		213	1/8"	3/8"	0.172"	0.374"	0.000" to 0.001"	-0.005" to 0.000"	ASME B17.2	Inch	50	000000000	00000


		8630 Alloy Steel



				3	1/8"	1/2"	0.194"	0.491"	0.000" to 0.001"	-0.006" to 0.000"	ASME B17.2	Inch	100	000000000	00000


				5	1/8"	5/8"	0.24"	0.612"	0.000" to 0.001"	-0.006" to 0.000"	ASME B17.2	Inch	100	000000000	00000
				7	1/8"	3/4"	0.303"	0.74"	0.000" to 0.001"	-0.006" to 0.000"	ASME B17.2	Inch	50	000000000	00000
				213	1/8"	3/8"	0.172"	0.374"	0.000" to 0.001"	-0.005" to 0.000"	ASME B17.2	Inch	50	000000000	00000


				316 Stainless Steel



						3	1/8"	1/2"	0.194"	0.491"	0.000" to 0.001"	-0.006" to 0.000"	ASME B17.2	Inch	5	000000000	00000


						5	1/8"	5/8"	0.25"	0.612"	0.000" to 0.001"	-0.005" to 0.000"	ASME B17.2	Inch	5	000000000	00000
						7	1/8"	3/4"	0.303"	0.74"	0.000" to 0.001"	-0.006" to 0.000"	ASME B17.2	Inch	1	000000000	0000
						213	1/8"	3/8"	0.172"	0.374"	0.000" to 0.001"	-0.005" to 0.000"	ASME B17.2	Inch	5	000000000	00000

Machine Keys

Straight keys, with a square or rectangular cross section, are the most common type of key. Install them in keyways to transmit torque from shafts to gears and other components. Machine keys are often the same material as the shaft and other components with which they are used. To use a key as a sacrificial part, choose a softer key that will shear off when parts are exposed to excessive force, preventing damage to expensive equipment.

1008-1045 Carbon Steel—Steel keys are strong and easy to machine. Since steel is the most common material, these keys work in many applications. Steel keys rust when exposed to moisture, so they should only be used in dry environments.

18-8 Stainless Steel—18-8 stainless steel keys offer a balance of strength and corrosion resistance. They may be mildly magnetic.

Oversized Tolerance—Slightly larger than the size listed in the table, oversized keys fit tightly in a keyway. Press them into place for use in high-torque applications or to replace a key in a worn keyway.

Undersized Tolerance—Slightly smaller than the size listed in the table, undersized keys are the choice when you need a slightly looser fit or when you have an inconsistent keyway. Use them when parts need to be taken apart frequently, such as for maintenance or prototyping.

ASME B17.1 Class 1—Keys that meet ASME B17.1 specifications conform to ASME standards for dimensions and tolerances.

			Tolerance
	Lg.	Tolerance Rating	Ht.	Wd.	Min. Hardness	Specs. Met	Pkg. Qty.		Pkg.
1008-1045 Carbon Steel







				1/8" × 1/8"

				1/4"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B50	ASME B17.1 Class 1	10	000000000	000000


				1/2"	Oversized	0.000" to 0.002"	0.000" to 0.002"	Rockwell B50	—	10	000000000	0000
				1/2"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B50	ASME B17.1 Class 1	10	000000000	0000
				3/4"	Oversized	0.000" to 0.002"	0.000" to 0.002"	Rockwell B50	—	10	000000000	00000
				3/4"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B50	ASME B17.1 Class 1	10	000000000	0000
				1"	Oversized	0.000" to 0.002"	0.000" to 0.002"	Rockwell B50	—	10	000000000	0000
				1"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B50	ASME B17.1 Class 1	10	000000000	0000
				1 1/4"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B50	ASME B17.1 Class 1	10	000000000	0000
				1 1/2"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B50	ASME B17.1 Class 1	10	000000000	0000


				18-8 Stainless Steel







								1/8" × 1/8"

								1/4"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B82	—	10	000000000	0000


								1/2"	Oversized	0.000" to 0.003"	0.000" to 0.003"	Rockwell B82	—	10	000000000	0000
								1/2"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B82	—	10	000000000	0000
								3/4"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B82	—	10	000000000	0000
								1"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B82	—	10	000000000	0000
								1 1/4"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B82	—	10	000000000	00000
								1 1/2"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B82	—	10	000000000	00000

Rounded Machine Keys

When installed, these keys fill oval keyways completely, reducing stress on the key and shaft. Using them in a closed keyway keeps them from sliding along the shaft axis. The rounded ends make it easy to slide gears, hubs, and other components into place. These are also known as feather keys. Machine keys are often the same material as the shaft and other components with which they are used. To use a key as a sacrificial part, choose a softer key that will shear off when parts are exposed to excessive force, preventing damage to expensive equipment.

Zinc-Plated 1008-1045 Carbon Steel— Zinc-plated steel keys resist corrosion in wet environments.

ASME B17.1 Class 1 and ASME B17.1 Class 2—Keys that meet ASME B17.1 specifications conform to ASME standards for dimensions and tolerances.

			Tolerance
	Lg.	Tolerance Rating	Ht.	Wd.	Min. Hardness	Specs. Met	Pkg. Qty.		Pkg.
1008-1045 Carbon Steel







				1/8" × 1/8"

				1/2"	Oversized	0.000" to 0.001"	0.000" to 0.001"	Not Rated	ASME B17.1 Class 2	5	000000000	00000


				1/2"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Not Rated	ASME B17.1 Class 1	5	000000000	0000
				3/4"	Oversized	0.000" to 0.001"	0.000" to 0.001"	Not Rated	ASME B17.1 Class 2	5	000000000	0000
				3/4"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Not Rated	ASME B17.1 Class 1	5	000000000	0000
				1"	Oversized	0.000" to 0.001"	0.000" to 0.001"	Not Rated	ASME B17.1 Class 2	5	000000000	0000
				1"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Not Rated	ASME B17.1 Class 1	5	000000000	0000


				Zinc-Plated 1008-1045 Carbon Steel







								1/8" × 1/8"

								1/2"	Oversized	0.000" to 0.001"	0.000" to 0.001"	Not Rated	ASME B17.1 Class 2	5	000000000	00000


								1/2"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Not Rated	ASME B17.1 Class 1	5	000000000	0000
								3/4"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Not Rated	ASME B17.1 Class 1	5	000000000	0000
								1"	Oversized	0.000" to 0.001"	0.000" to 0.001"	Not Rated	ASME B17.1 Class 2	5	000000000	00000
								1"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Not Rated	ASME B17.1 Class 1	5	000000000	0000

Machine Key Stock

Cut this square or rectangular key stock to length to create a straight machine key. Straight keys are the most common type of key. Machine keys are often the same material as the shaft and other components with which they are used. To use a key as a sacrificial part, choose a softer key that will shear off when parts are exposed to excessive force, preventing damage to expensive equipment.

1008-1045 Carbon Steel

1008-1045 carbon steel key stock is an economical choice with good strength.

Oversized Tolerance—Slightly larger than the size listed in the table, oversized stock fits tightly in a keyway. Press it into place for use in high-torque applications or to replace a key in a worn keyway.

Undersized Tolerance—Slightly smaller than the size listed in the table, undersized stock is the choice when you need a slightly looser fit or when you have an inconsistent keyway. Use it when parts need to be taken apart frequently, such as for maintenance or prototyping.

			Tolerance
	Ht. × Wd.	Tolerance Rating	Ht.	Wd.	Min. Hardness		Each
12" Long



		1/8" × 1/8"	Oversized	0.000" to 0.002"	0.000" to 0.002"	Rockwell B50	000000000	00000


		1/8" × 1/8"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B50	000000000	0000


		36" Long



				1/8" × 1/8"	Oversized	0.000" to 0.002"	0.000" to 0.002"	Rockwell B50	000000000	0000


				1/8" × 1/8"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B50	000000000	0000


				72" Long



						1/8" × 1/8"	Oversized	0.000" to 0.002"	0.000" to 0.002"	Rockwell B50	000000000	0000

Zinc-Plated 1008-1045 Carbon Steel

Zinc-plated 1008-1045 carbon steel key stock is an economical choice with good strength and resists corrosion in wet environments.

			Tolerance
	Ht. × Wd.	Tolerance Rating	Ht.	Wd.	Min. Hardness		Each
12" Long



		1/8" × 1/8"	Oversized	0.000" to 0.002"	0.000" to 0.002"	Rockwell B50	000000000	00000


		1/8" × 1/8"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B50	000000000	0000


		36" Long



				1/8" × 1/8"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B50	000000000	0000

1095 Spring Steel

1095 spring steel key stock is an economical choice with good strength.

			Tolerance
	Ht. × Wd.	Tolerance Rating	Ht.	Wd.	Min. Hardness		Each
12" Long



		1/8" × 1/8"	Standard	-0.001" to 0.001"	-0.001" to 0.001"	Rockwell B90	000000000	00000


		36" Long



				1/8" × 1/8"	Standard	-0.001" to 0.001"	-0.001" to 0.001"	Rockwell B90	000000000	00000

8630 Alloy Steel

8630 alloy steel key stock is an economical choice with good strength.

ASME B17.1 Class 2—Key stock that meets ASME B17.1 Class 2 specifications conforms to ASME standards for dimensions and tolerances.

			Tolerance
	Ht. × Wd.	Tolerance Rating	Ht.	Wd.	Min. Hardness	Specs. Met		Each
12" Long



		1/8" × 1/8"	Oversized	0.000" to 0.001"	0.000" to 0.001"	Rockwell B50	ASME B17.1 Class 2	000000000	00000


		1/8" × 1/8"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Not Rated	—	000000000	0000

18-8 Stainless Steel

18-8 stainless steel key stock offers a balance of strength and corrosion resistance. It may be mildly magnetic. 18-8 stainless steel key stock is more corrosion resistant than steel key stock.

			Tolerance
	Ht. × Wd.	Tolerance Rating	Ht.	Wd.	Min. Hardness		Each
12" Long



		1/8" × 1/8"	Oversized	0.000" to 0.003"	0.000" to 0.003"	Rockwell B82	000000000	00000


		1/8" × 1/8"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B82	000000000	0000


		36" Long



				1/8" × 1/8"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B82	000000000	0000

316/316L Stainless Steel

316/316L stainless steel key stock has the best corrosion resistance of our stainless steel key stock and may be mildly magnetic. 316/316L stainless steel key stock is more corrosion resistant than steel key stock.

			Tolerance
	Ht. × Wd.	Tolerance Rating	Ht.	Wd.	Min. Hardness		Each
12" Long



		1/8" × 1/8"	Oversized	0.000" to 0.002"	0.000" to 0.002"	Not Rated	000000000	00000


		1/8" × 1/8"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B86	000000000	0000
		1/4" × 1/8"	Oversized	0.000" to 0.003"	0.000" to 0.003"	Not Rated	000000000	00000


		36" Long



				1/8" × 1/8"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B86	000000000	00000

400 Nickel

400 nickel key stock is the most corrosion resistant key stock in our offering and can be used in highly corrosive environments, such as those involving salt water, sulfuric acid, and alkalies. For complete corrosion resistance, 400 nickel keys are typically used with 400 nickel machine parts. Comparable to Monel, 400 nickel is also known for its strength and weldability.

			Tolerance
	Ht. × Wd.	Tolerance Rating	Ht.	Wd.	Min. Hardness		Each
12" Long



		1/8" × 1/8"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B61	0000000	000000


		36" Long



				1/8" × 1/8"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B61	0000000	000000

360 Brass

360 brass key stock is corrosion resistant and nonmagnetic. 360 brass is softer than other metals, so it's often used for shear keys.

			Tolerance
	Ht. × Wd.	Tolerance Rating	Ht.	Wd.	Min. Hardness		Each
12" Long



		1/8" × 1/8"	Standard	-0.0035" to 0.0035"	-0.0035" to 0.0035"	Rockwell B35	000000000	00000


		36" Long



				1/8" × 1/8"	Standard	-0.0035" to 0.0035"	-0.0035" to 0.0035"	Rockwell B35	000000000	0000

6061 Aluminum

6061 aluminum key stock is one-third the weight of steel key stock, but not as strong. It resists corrosion and is nonmagnetic.

			Tolerance
	Ht. × Wd.	Tolerance Rating	Ht.	Wd.	Min. Hardness		Each
12" Long



		1/8" × 1/8"	Standard	-0.008" to 0.008"	-0.008" to 0.008"	Not Rated	000000000	000000

High-Profile Woodruff Keys


	Side View

Feet prevent these keys from rocking in the keyseat, making it easier to install gears and other components. Woodruff keys work well near shaft shoulders, where a standard open keyway would create too much stress. They are also often used on tapered shafts. Because they're usually shorter than standard machine keys, they work best in light duty applications. Keys are made of steel. Also known as hi-pro keys.

						Tolerance
	Woodruff Key No.	Wd.	Ht.	For Keyway Dia.	Lg.	Wd.	Ht.	Feet Ht.	Pkg. Qty.		Pkg.
1018-1045 Carbon Steel



		3	1/8"	0.194"	1/2"	0.531"	0.000" to 0.001"	0.000" to 0.006"	0.056"	5	000000000	00000


		5	1/8"	0.24"	5/8"	0.656"	0.000" to 0.001"	0.000" to 0.006"	0.056"	5	000000000	0000
		7	1/8"	0.303"	3/4"	0.781"	0.000" to 0.001"	0.000" to 0.006"	0.057"	5	000000000	0000