M2 Couplings | McMaster-Carr

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27 Products

Coupling Nuts

Also known as extension nuts, these are commonly used to connect lengths of threaded rod and join threaded parts.

Low-Strength Steel

Rated Grade 2 or lower, these are about half as strong as medium-strength steel coupling nuts. Use them with threaded rods that have a comparable strength rating to avoid stripping threads during installation.

Zinc-Plated Steel—A step up from plain steel, the zinc plating withstands occasional exposure to moisture.

Black-Oxide Steel—A dark, matte coating creates a finished look. Nuts offer minimal corrosion resistance, so they're best for dry environments.

						Each
	Thread Size	Lg., mm	Wd., mm	Threading		1-9	10-49	50-Up
Zinc-Plated Steel



		M2 × 0.4 mm	6	4.5	Fully Threaded	93355A510	00000	00000	00000


		M2 × 0.4 mm	12	4.5	Fully Threaded	90264A801	0000	0000	0000


		Black-Oxide Steel



				M2 × 0.4 mm	6	4.5	Fully Threaded	93020A101	0000	0000	0000

Corrosion-Resistant Stainless Steel

18-8 Stainless Steel—The choice for wet and outdoor environments, these nuts resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.

Black-Oxide 18-8 Stainless Steel—Typically chosen for their appearance, these nuts have a dark, matte coating to create a finished look. They resist rust in wet and outdoor environments, but won't hold up to the harsh chemicals that 316 stainless steel can.

						Each
	Thread Size	Lg., mm	Wd., mm	Threading		1-9	10-49	50-Up
18-8 Stainless Steel



		M2 × 0.4 mm	6	4	Fully Threaded	93590A101	00000	00000	00000


		Black-Oxide 18-8 Stainless Steel



				M2 × 0.4 mm	6	4	Fully Threaded	93590A317	0000	0000	0000

Lightweight Aluminum

6061 Aluminum—One-third the weight of steel, these nuts are commonly used in robotics, automation, and other applications that have weight limitations. They're an alternative to stainless steel for rust resistance but are not as strong.

						Each
	Thread Size	Lg., mm	Wd., mm	Threading		1-9	10-49	50-Up
6061 Aluminum



		M2 × 0.4 mm	6	4.5	Fully Threaded	90012A210	00000	00000	00000

Brass

Brass—With a warm, polished look, these nuts are often chosen for their appearance. Similar to 18-8 stainless steel, brass is corrosion resistant enough to stand up to wet environments. It is also softer than other metals, so it's easier to thread together.

						Each
	Thread Size	Lg., mm	Wd., mm	Threading		1-9	10-49	50-Up
Brass



		M2 × 0.4 mm	6	4	Fully Threaded	90465A411	000000	000000	000000

Plastic

Nylon 6/6—Slippery and abrasion resistant, these nuts thread on smoothly and stand up to daily wear and tear. Nylon will swell and weaken when exposed to moisture, so it's best for dry environments.

					Temp., ° F				Each
	Thread Size	Lg., mm	Wd., mm	Threading	Min.	Max.	Color		1-9	10-49	50-Up
Nylon 6/6



		M2 × 0.4 mm	6	4	Fully Threaded	-40	250	Off-White	1319N21	00000	00000	00000

Slotted-Drive Male-Female Round Thread Adapters

18-8 Stainless Steel—18-8 stainless steel adapters resist corrosion better than brass adapters. They also withstand wet environments.

			Thread Lg., mm		Gender		Thread Fit
	Thread Size (A)	Thread Size (B)	(A)	(B)	(A)	(B)	(A)	(B)	Hardness		Each
18-8 Stainless Steel



		M4 x 0.7 mm	M2 x 0.4 mm	6.4	6.4	Male	Female	Metric Class 6g	Metric Class 6H	Not Rated	97437A814	00000

Miniature Splined Press-Fit Threaded Standoffs

Fully

Threaded

The smallest standoffs we offer. These press into unthreaded holes to create permanent connections without welding, tapping, or installing extra hardware. The raised splines prevent rotation, and a recessed head clinches material for a strong hold. A through hole allows installation from one side, making them ideal for compact electronics like laptops and handheld devices.

Wear-Resistant 400 Series Stainless Steel—These standoffs can grind against metal surfaces without denting or scratching. More corrosion resistant than steel.

	Thread Lg., mm	For Hole Dia., mm	Specs. Met	Pkg. Qty.		Pkg.
Wear-Resistant 400 Series Stainless Steel







	M2 × 0.4 mm

	2	3.2	Fully Threaded	2	3.2	ASTM A380	25	92985A817	00000


	3	3.2	Fully Threaded	3	3.2	ASTM A380	25	92985A818	0000

Metric Ultra-Precision Lead Screws and Nuts


Style A	Style B	Style C

Operating with less backlash (play) than Metric Precision Acme Lead Screws and Nuts, these provide increased nut life and more reliable movement in automated systems. Also known as single-start and self-locking lead screws and nuts, they have a single thread that runs the length of the screw. The nut travels only when the screw turns, so your system won't unexpectedly move when the lead screw is at rest. To ensure compatibility, select components that have the same thread size, thread type, thread size, thread pitch, and number of thread starts.

Externally Threaded Nuts—Right-Hand Thread


Style A	Style B

Acetal—Acetal nuts have good wear and corrosion resistance.

Travel Distance per Turn—Travel distance per turn, also known as screw lead, is the distance a nut moves with one revolution of the lead screw.

												External Thread
	Style	Thread Size	Lg.	Wd.	Ht.	Dia.	Hex Wd.	Thread Type	Speed Ratio	No. of Thread Starts	Travel Distance per Turn, mm	Size	Lg.	Hardness	Tensile Strength, psi	Dynamic Thrust Load Cap., lb.	Temp., ° F		Each
Acetal



		A	M2 × 0.5 mm	11/16"	—	—	0.297"	7/16"	Metric Rounded Trapezoidal	1:1	1	0.5	3/8"-24	3/16"	Not Rated	8,000	10	-40 to 185	7549K58	000000


		PEEK



				B	M2 × 0.4 mm	5/16"	0.22"	0.197"	—	—	Metric Rounded Trapezoidal	1:1	1	0.375	M5 × 0.8 mm	9/64"	Durometer 83D	Not Rated	2	—	90500A220	00000

Flange Nuts—Right-Hand Thread


Style C	Style C

Acetal—Acetal nuts have good wear and corrosion resistance.

Wear-Compensating Internal O-Ring—Flange nuts with wear-compensating internal O-ring maintain a tight fit even when their threads begin to wear. They resist backlash to maintain accuracy over time, which is important in positioning applications such as 3D printing and robotics.

Travel Distance per Turn—Travel distance per turn, also known as screw lead, is the distance a nut moves with one revolution of the lead screw.

					Flange
	Style	Thread Size	Lg.	Dia.	Wd.	Ht.	Thk.	Thread Type	Speed Ratio	Bolt Circle Dia.	No. of Thread Starts	Travel Distance per Turn, mm	Hardness	Tensile Strength, psi	Dynamic Thrust Load Cap., lb.	No. of Mounting Holes	Temp., ° F		Each
Acetal



		C	M2 × 0.5 mm	1/2"	0.297"	3/4"	13/32"	1/8"	Metric Rounded Trapezoidal	1:1	39/64"	1	0.5	Not Rated	8,000	10	2	-40 to 185	7549K62	000000


		PEEK



				C	M2 × 0.4 mm	9/32"	0.209"	15/32"	15/64"	5/64"	Metric Rounded Trapezoidal	1:1	11/32"	1	0.375	Durometer 83D	Not Rated	2	2	—	90500A250	00000


				PEEK with Wear-Compensating Internal O-Ring



						C	M2 × 0.4 mm	5/16"	0.228"	15/32"	15/64"	5/64"	Metric Rounded Trapezoidal	1:1	11/32"	1	0.375	Durometer 83D	Not Rated	1	2	—	90500A280	000000

Metric Fast-Travel Ultra-Precision Lead Screws and Nuts


	Style B	Style C	Style D

Multiple thread channels (also known as thread starts) create faster linear travel than lead screws with a single thread start. Operating with less backlash (play) than Metric Precision Acme Lead Screws and Nuts, these lead screws and nuts provide increased nut life and more reliable movement in automated systems. To ensure compatibility, select components that have the same thread size and number of thread starts.

Externally Threaded Nuts—Right-Hand Thread


Style B	Style C

Acetal—Acetal nuts have good wear and corrosion resistance.

Travel Distance per Turn—Travel distance per turn, also known as screw lead, is the distance a nut moves with one revolution of the lead screw.

												External Thread
	Style	Thread Size	Lg.	Wd.	Ht.	Dia.	Hex Wd.	Thread Type	Speed Ratio	No. of Thread Starts	Travel Distance per Turn, mm	Size	Lg.	Hardness	Tensile Strength, psi	Dynamic Thrust Load Cap., lb.	Temp., ° F		Each
Acetal



		B	M2 × 0.5 mm	11/16"	—	—	0.297"	7/16"	Metric Rounded Trapezoidal	2:1	2	1	3/8"-24	3/16"	Not Rated	8,000	10	-40 to 185	97783A190	000000


		PEEK



				C	M2 × 0.4 mm	5/16"	0.22"	0.197"	—	—	Metric Rounded Trapezoidal	2:1	2	0.75	M5 × 0.8 mm	9/64"	Durometer 83D	Not Rated	2	—	4537N161	00000


				C	M2 × 0.4 mm	5/16"	0.22"	0.197"	—	—	Metric Rounded Trapezoidal	4:1	4	1.5	M5 × 0.8 mm	9/64"	Durometer 83D	Not Rated	2	—	4537N162	00000
				C	M2 × 0.4 mm	5/16"	0.22"	0.197"	—	—	Metric Rounded Trapezoidal	8:1	8	3	M5 × 0.8 mm	9/64"	Durometer 83D	Not Rated	2	—	4537N163	00000

Flange Nuts—Right-Hand Thread


Style D	Style D

Acetal—Acetal nuts have good wear and corrosion resistance.

Wear-Compensating Internal O-Ring—Flange nuts with a wear-compensating internal O-ring resist backlash to keep the nuts in place and maintain a tight fit even when their threads begin to wear. They’re often used in 3D printing and robotic applications.

Travel Distance per Turn—Travel distance per turn, also known as screw lead, is the distance a nut moves with one revolution of the lead screw.

					Flange
	Style	Thread Size	Lg.	Dia.	Wd.	Ht.	Thk.	Thread Type	Speed Ratio	Bolt Circle Dia.	No. of Thread Starts	Travel Distance per Turn, mm	Hardness	Tensile Strength, psi	Dynamic Thrust Load Cap., lb.	No. of Mounting Holes	Temp., ° F		Each
Acetal



		D	M2 × 0.5 mm	1/2"	0.297"	3/4"	13/32"	1/8"	Metric Rounded Trapezoidal	2:1	39/64"	2	1	Not Rated	8,000	10	2	-40 to 185	97783A240	000000


		PEEK



				D	M2 × 0.4 mm	9/32"	0.209"	15/32"	15/64"	5/64"	Metric Rounded Trapezoidal	2:1	11/32"	2	0.75	Durometer 83D	Not Rated	2	2	—	4537N181	00000


				D	M2 × 0.4 mm	9/32"	0.209"	15/32"	15/64"	5/64"	Metric Rounded Trapezoidal	4:1	11/32"	4	1.5	Durometer 83D	Not Rated	2	2	—	4537N182	00000
				D	M2 × 0.4 mm	9/32"	0.209"	15/32"	15/64"	5/64"	Metric Rounded Trapezoidal	8:1	11/32"	8	3	Durometer 83D	Not Rated	2	2	—	4537N183	00000


				PEEK with Wear-Compensating Internal O-Ring



						D	M2 × 0.4 mm	5/16"	0.228"	15/32"	15/64"	5/64"	Metric Rounded Trapezoidal	2:1	11/32"	2	0.75	Durometer 83D	Not Rated	1	2	—	4537N201	00000


						D	M2 × 0.4 mm	5/16"	0.228"	15/32"	15/64"	5/64"	Metric Rounded Trapezoidal	4:1	11/32"	4	1.5	Durometer 83D	Not Rated	1	2	—	4537N202	00000
						D	M2 × 0.4 mm	5/16"	0.228"	15/32"	15/64"	5/64"	Metric Rounded Trapezoidal	8:1	11/32"	8	3	Durometer 83D	Not Rated	1	2	—	4537N203	00000