5/16" Keys | McMaster-Carr

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Material

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Tolerance Rating

For Keyway Diameter

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Hardness

Woodruff Key Number

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Yes

DFARS Specialty Metals

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Specifications Met

REACH

Export Control Classification Number (ECCN)

EAR99

Shape

Rectangle

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Zinc Plated

For Machine Table T-Slot Width

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Head Length

Rate of Taper

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58 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.

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



		23	5/16"	1 3/8"	0.584"	1.362"	0.000" to 0.001"	-0.006" to 0.000"	ASME B17.2	Inch	10	98481A245	000000


		25	5/16"	1 1/2"	0.631"	1.484"	0.000" to 0.001"	-0.006" to 0.000"	ASME B17.2	Inch	10	98481A260	00000
		B	5/16"	1"	0.428"	0.992"	0.000" to 0.001"	-0.006" to 0.000"	ASME B17.2	Inch	25	98481A175	00000
		C	5/16"	1 1/8"	0.475"	1.114"	0.000" to 0.001"	-0.006" to 0.000"	ASME B17.2	Inch	25	98481A210	00000
		D	5/16"	1 1/4"	0.537"	1.24"	0.000" to 0.001"	-0.006" to 0.000"	ASME B17.2	Inch	10	98481A235	00000


		8630 Alloy Steel



				23	5/16"	1 3/8"	0.584"	1.362"	0.000" to 0.001"	-0.006" to 0.000"	ASME B17.2	Inch	10	98525A245	00000


				25	5/16"	1 1/2"	0.631"	1.484"	0.000" to 0.001"	-0.006" to 0.000"	ASME B17.2	Inch	10	98525A260	00000
				B	5/16"	1"	0.428"	0.992"	0.000" to 0.001"	-0.006" to 0.000"	ASME B17.2	Inch	10	98525A175	0000
				C	5/16"	1 1/8"	0.475"	1.114"	0.000" to 0.001"	-0.006" to 0.000"	ASME B17.2	Inch	10	98525A210	00000
				D	5/16"	1 1/4"	0.537"	1.24"	0.000" to 0.001"	-0.006" to 0.000"	ASME B17.2	Inch	10	98525A235	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 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







				5/16" × 5/16"

				1 1/4"	Oversized	0.000" to 0.001"	0.000" to 0.001"	Not Rated	ASME B17.1 Class 2	5	98870A324	00000


				1 1/4"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B50	ASME B17.1 Class 1	10	98870A275	0000
				1 1/2"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B50	ASME B17.1 Class 1	10	98870A277	0000
				2"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B50	ASME B17.1 Class 1	10	98870A281	00000
				2 1/2"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B50	ASME B17.1 Class 1	10	98870A283	00000


				18-8 Stainless Steel







								5/16" × 5/16"

								1 1/4"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B97	—	5	92624A275	00000


								1 1/2"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B97	—	5	92624A277	00000
								2"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B97	—	5	92624A281	00000
								2 1/2"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B97	—	5	92624A283	00000

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



		1/4" × 5/16"	Oversized	0.000" to 0.003"	0.000" to 0.003"	Rockwell B50	98830A528	00000


		1/4" × 5/16"	Undersized	-0.003" to 0.000"	-0.003" to 0.000"	Rockwell B50	98830A529	0000
		5/16" × 5/16"	Oversized	0.000" to 0.002"	0.000" to 0.002"	Rockwell B50	98830A250	0000
		5/16" × 5/16"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B50	98830A535	0000


		36" Long



				5/16" × 5/16"	Oversized	0.000" to 0.002"	0.000" to 0.002"	Rockwell B50	98830A879	0000


				5/16" × 5/16"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B50	98830A536	0000


				72" Long



						5/16" × 5/16"	Oversized	0.000" to 0.002"	0.000" to 0.002"	Rockwell B50	98830A580	00000

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



		3/16" × 5/16"	Oversized	0.000" to 0.003"	0.000" to 0.003"	Rockwell B50	98491A119	00000


		3/16" × 5/16"	Undersized	-0.003" to 0.000"	-0.003" to 0.000"	Rockwell B50	98510A140	0000
		1/4" × 5/16"	Oversized	0.000" to 0.003"	0.000" to 0.003"	Rockwell B50	98491A137	0000
		1/4" × 5/16"	Undersized	-0.003" to 0.000"	-0.003" to 0.000"	Rockwell B50	98510A145	0000
		5/16" × 5/16"	Oversized	0.000" to 0.002"	0.000" to 0.002"	Rockwell B50	98491A150	0000
		5/16" × 5/16"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B50	98510A150	0000


		36" Long



				5/16" × 5/16"	Oversized	0.000" to 0.002"	0.000" to 0.002"	Rockwell B50	98491A419	00000


				5/16" × 5/16"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Rockwell B50	98491A421	00000

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



		1/4" × 5/16"	Standard	-0.001" to 0.001"	-0.001" to 0.001"	Rockwell B90	98535A152	000000


		5/16" × 5/16"	Standard	-0.001" to 0.001"	-0.001" to 0.001"	Rockwell B90	98535A160	0000


		36" Long



				5/16" × 5/16"	Standard	-0.001" to 0.001"	-0.001" to 0.001"	Rockwell B90	98535A560	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



		5/16" × 5/16"	Oversized	0.000" to 0.001"	0.000" to 0.001"	Rockwell B50	ASME B17.1 Class 2	99020A430	00000


		5/16" × 5/16"	Undersized	-0.002" to 0.000"	-0.002" to 0.000"	Not Rated	—	99020A819	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



		5/16" × 5/16"	Oversized	0.000" to 0.003"	0.000" to 0.003"	Rockwell B82	98493A150	00000


		5/16" × 5/16"	Undersized	-0.003" to 0.000"	-0.003" to 0.000"	Rockwell B82	92530A150	0000


		36" Long



				5/16" × 5/16"	Oversized	0.000" to 0.003"	0.000" to 0.003"	Rockwell B82	92530A316	00000


				5/16" × 5/16"	Undersized	-0.003" to 0.000"	-0.003" to 0.000"	Rockwell B82	92530A317	00000

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



		1/4" × 5/16"	Undersized	-0.003" to 0.000"	-0.003" to 0.000"	Rockwell B86	98530A137	000000


		5/16" × 5/16"	Oversized	0.000" to 0.002"	0.000" to 0.002"	Not Rated	98530A778	00000
		5/16" × 5/16"	Undersized	-0.003" to 0.000"	-0.003" to 0.000"	Rockwell B86	98530A150	00000
		3/8" × 5/16"	Oversized	0.000" to 0.003"	0.000" to 0.003"	Not Rated	98530A742	00000


		36" Long



				5/16" × 5/16"	Undersized	-0.003" to 0.000"	-0.003" to 0.000"	Rockwell B86	98530A420	00000

416 Stainless Steel

416 stainless steel key stock is stronger than other stainless key stock and can be heat treated for extra strength. It's corrosion resistant and magnetic. 416 stainless steel key stock is more corrosion resistant than steel key stock.

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



		5/16" × 5/16"	Undersized	-0.003" to 0.000"	-0.003" to 0.000"	Rockwell B86	99374A120	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



		5/16" × 5/16"	Standard	-0.0035" to 0.0035"	-0.0035" to 0.0035"	Rockwell B35	98500A150	000000


		36" Long



				5/16" × 5/16"	Standard	-0.0035" to 0.0035"	-0.0035" to 0.0035"	Rockwell B35	98500A151	00000

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



		5/16" × 5/16"	Standard	-0.008" to 0.008"	-0.008" to 0.008"	Not Rated	99108A105	000000

Nylon 6/6

Nylon 6/6 key stock is slippery and wear resistant.

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



		5/16" × 5/16"	Undersized	-0.003" to 0.000"	-0.003" to 0.000"	Durometer 80D	94446A880	000000

Tapered Gib Keys

These keys have a tapered body that wedges in to the keyway for a more secure fit than standard machine keys. The gib head makes these keys easy to remove when parts need to be taken apart frequently, such as for maintenance or prototyping. Keys are tapered along their length. Use them to connect gears and other components with tapered keyways to shafts. Keys are made of steel.

Inch—The height of inch keys decreases by _1/8" for every 12" of length. They conform to ASME B17.1 Class 1 standards for dimensions and tolerances.

		Tolerance		Head
	Lg.	Ht.	Wd.	Ht.	Lg.	End Ht.	Rate of Taper	Specs. Met	System of Measurement		Each
1018-1045 Carbon Steel







				5/16" × 5/16"

				2"	-0.002" to 0.000"	-0.002" to 0.000"	1/2"	7/16"	0.295"	1:96	ASME B17.1 Class 1	Inch	98471A142	00000


				2 1/2"	-0.002" to 0.000"	-0.002" to 0.000"	1/2"	7/16"	0.290"	1:96	ASME B17.1 Class 1	Inch	98471A143	0000
				3"	-0.002" to 0.000"	-0.002" to 0.000"	1/2"	7/16"	0.285"	1:96	ASME B17.1 Class 1	Inch	98471A144	0000
				4"	-0.002" to 0.000"	-0.002" to 0.000"	1/2"	7/16"	0.274"	1:96	ASME B17.1 Class 1	Inch	98471A146	0000

Fixture Keys


	Rectangle

Sized to fit with precision in machine table T-slots, use these keys to locate fixtures and vises on your machine table. They mount to the underside of your fixture or vise with a socket head cap screw.

	Ht.	Wd. Tolerance	For Mounting Screw Size	Mounting Fasteners Included		Each
Rectangle







	Steel

	5/16"	3/4"	5/16"	1/2"	-0.0005" to 0"	No. 4	No	8961A11	00000