5mm Keys | McMaster-Carr

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	System of Measurement System of Measurement

Metric

	Width Width	Show

5mm

	Width Width	Hide

	Overall Length Overall Length

	Height Height

	Material Material

Brass

Stainless Steel

Steel

	Key Type Key Type


Straight	Rounded

Woodruff

	Tolerance Rating Tolerance Rating

Undersized

Oversized

	Specifications Met Specifications Met

	Minimum Hardness Minimum Hardness

	RoHS (Restriction of Hazardous Substances) RoHS (Restriction of Hazardous Substances)

RoHS Compliant

RoHS Compliant with
Exemptions

	REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) REACH (Registration, Evaluation, Authorization and Restriction of Chemicals)

REACH Compliant

	DFARS (Defense Acquisition Regulations Supplement) DFARS (Defense Acquisition Regulations Supplement)

DFARS Specialty Metals
COTS-Exempt

DFARS Specialty Metals
Compliant

	For Keyway Diameter For Keyway Diameter

	Thread Size Thread Size

	Thread Pitch Thread Pitch

0.5 mm

	For Maximum Keyway Diameter Tolerance For Maximum Keyway Diameter Tolerance

0.000mm

	For Minimum Keyway Diameter Tolerance For Minimum Keyway Diameter Tolerance

-0.200mm

-0.100mm

	Finish Finish

Zinc Plated

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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 and as hard or harder than 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.

Steel keys offer good strength.

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

Metric keys conform to DIN 6885 standards.

For technical drawings and 3-D models, click on a part number.

		Tolerance
Lg.	Tolerance Rating	Ht.	Wd.	Specifications Met	Pkg. Qty.		Pkg.
1018-1045 Carbon Steel
5mm × 5mm
10mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	10	000000000	00000
12mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	10	000000000	0000
14mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	10	000000000	00000
16mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	10	000000000	0000
18mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	10	000000000	00000
20mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	10	000000000	0000
22mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	5	000000000	0000
25mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	10	000000000	0000
28mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	5	000000000	0000
30mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	1	000000000	0000
32mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	5	000000000	0000
36mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	5	000000000	0000
40mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	1	000000000	0000
45mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	5	000000000	0000
50mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	1	000000000	0000
316 Stainless Steel
5mm × 5mm
8mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	5	0000000	00000
10mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	5	0000000	00000
12mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	5	0000000	00000
14mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	5	0000000	00000
15mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	5	0000000	00000
16mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	5	0000000	00000
18mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	1	0000000	0000
20mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	1	000000000	0000
22mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	5	0000000	00000
25mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	1	0000000	0000
28mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	5	0000000	00000
30mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	1	000000000	0000
35mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	5	0000000	00000
36mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	1	0000000	0000
40mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	1	0000000	0000
45mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	1	0000000	0000
50mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	1	0000000	0000
60mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	1	0000000	0000
63mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	1	0000000	0000
70mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	DIN 6885	1	0000000	0000

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.

Steel keys offer good strength.

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

Metric keys conform to DIN 6888 standards.

For technical drawings and 3-D models, click on a part number.

				Tolerance
Wd.	For Keyway Dia.	Ht.	Lg.	Wd.	Ht.	Specifications Met	Pkg. Qty.		Pkg.
1018-1045 Carbon Steel
5mm	16mm	6.5mm	15.7mm	-0.030mm to 0.000mm	__	DIN 6888	25	000000000	000000
5mm	19mm	7.5mm	18.6mm	-0.030mm to 0.000mm	__	DIN 6888	25	000000000	00000
5mm	22mm	9mm	21.6mm	-0.030mm to 0.000mm	__	DIN 6888	25	000000000	00000
5mm	25mm	10mm	24.5mm	-0.030mm to 0.000mm	__	DIN 6888	10	000000000	00000
316 Stainless Steel
5mm	16mm	6.5mm	15.7mm	-0.030mm to 0.000mm	-0.150mm to 0.000mm	DIN 6888	1	000000000	00000
5mm	19mm	7.5mm	18.6mm	-0.030mm to 0.000mm	-0.150mm to 0.000mm	DIN 6888	1	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 and as hard or harder than 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.

Steel keys offer good strength.

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.

For technical drawings and 3-D models, click on a part number.

		Tolerance
Lg.	Tolerance Rating	Ht.	Wd.	Minimum Hardness	Specifications Met	Pkg. Qty.		Pkg.
1008-1045 Carbon Steel
5mm × 5mm
10mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	00000
12mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
14mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
16mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
18mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
20mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
22mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
25mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
28mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
30mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
32mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
36mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
40mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
45mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
50mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
316 Stainless Steel
5mm × 5mm
8mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
10mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
12mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
15mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
16mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
18mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
20mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	0000
25mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	00000
30mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	00000
35mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	00000
40mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	00000
50mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	00000
55mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	5	000000000	00000
70mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6885	1	000000000	0000

Tapped Rounded Machine Keys

Thread a screw through the tapped hole to pop these keys out of a keyway. When installed, they 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. To install, press them in to place. Use them for permanent or high-torque applications, or to replace a key in a worn keyway. Keys are made of steel.

Undersized keys are good when you need a slightly looser fit or when you have an inconsistent keyway. Use them with parts you take apart frequently, such as for maintenance or prototyping. They meet DIN 6885 dimensional standards for undersized keys.

For technical drawings and 3-D models, click on a part number.

		Tolerance
Lg.	Tolerance Rating	Ht.	Wd.	Thread Size	Specifications Met		Each
1018-1045 Carbon Steel
5 mm × 5 mm
20mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	M3 × 0.5 mm	DIN 6885	000000000	00000
25mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	M3 × 0.5 mm	DIN 6885	000000000	0000
40mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	M3 × 0.5 mm	DIN 6885	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 and as hard or harder than 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.

Steel key stock is an economical choice with good strength. 4140 alloy steel key stock has greater strength and toughness after hardening than carbon steel, making it useful for high-stress applications. Zinc-plated steel key stock resists corrosion in wet environments.

Stainless steel key stock is more corrosion resistant than steel key stock. 18-8 stainless steel key stock offers a balance of strength and corrosion resistance. It may be mildly magnetic. 304 stainless steel key stock offers a good balance of strength, corrosion resistance, and machinability. 316 stainless steel key stock has the best corrosion resistance of our stainless steel key stock and may be mildly magnetic.

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

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. 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.

Key stock that meets DIN 6880 conforms to DIN standards for undersized keys.

For technical drawings and 3-D models, click on a part number.

1018-1045 Carbon Steel

		Tolerance
Ht. × Wd.	Tolerance Rating	Ht.	Wd.	Minimum Hardness	Specifications Met		Each
305mm Lg.
3mm × 5mm	Undersized	-0.060mm to 0.000mm	-0.030mm to 0.000mm	Rockwell B87	DIN 6880	000000000	00000
5mm × 5mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Rockwell B87	DIN 6880	000000000	0000
1,000mm Lg.
3mm × 5mm	Undersized	-0.060mm to 0.000mm	-0.030mm to 0.000mm	Rockwell B87	DIN 6880	000000000	00000
5mm × 5mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Rockwell B87	DIN 6880	000000000	0000

4140 Alloy Steel

		Tolerance
Ht. × Wd.	Tolerance Rating	Ht.	Wd.	Minimum Hardness	Specifications Met		Each
305mm Lg.
5mm × 5mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Rockwell B90	DIN 6880	000000000	00000
1,000mm Lg.
5mm × 5mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Rockwell B90	DIN 6880	000000000	00000

Zinc-Plated 1018-1045 Carbon Steel

		Tolerance
Ht. × Wd.	Tolerance Rating	Ht.	Wd.	Minimum Hardness	Specifications Met		Each
305mm Lg.
5mm × 5mm	Oversized	0.000mm to 0.076mm	0.000mm to 0.076mm	Rockwell B87	DIN 6880	000000000	00000

18-8 Stainless Steel

		Tolerance
Ht. × Wd.	Tolerance Rating	Ht.	Wd.	Minimum Hardness	Specifications Met		Each
305mm Lg.
5mm × 5mm	Oversized	0.000mm to 0.076mm	0.000mm to 0.076mm	Rockwell B82	DIN 178	000000000	00000
5mm × 5mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Not Rated	DIN 6880	000000000	0000

304 Stainless Steel

		Tolerance
Ht. × Wd.	Tolerance Rating	Ht.	Wd.	Minimum Hardness	Specifications Met		Each
1,000mm Lg.
3mm × 5mm	Undersized	-0.060mm to 0.000mm	-0.030mm to 0.000mm	Rockwell B80	DIN 6880	000000000	000000
5mm × 5mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Rockwell B80	DIN 6880	000000000	00000

316 Stainless Steel

		Tolerance
Ht. × Wd.	Tolerance Rating	Ht.	Wd.	Minimum Hardness	Specifications Met		Each
305mm Lg.
5mm × 5mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Rockwell B86	DIN 6880	000000000	00000
1,000mm Lg.
3mm × 5mm	Undersized	-0.060mm to 0.000mm	-0.030mm to 0.000mm	Rockwell B85	DIN 6880	000000000	00000
5mm × 5mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Rockwell B85	DIN 6880	000000000	00000

360 Brass

		Tolerance
Ht. × Wd.	Tolerance Rating	Ht.	Wd.	Minimum Hardness	Specifications Met		Each
305mm Lg.
5mm × 5mm	Undersized	-0.030mm to 0.000mm	-0.030mm to 0.000mm	Rockwell B35	DIN 6880	000000000	000000