7/8"-9 Couplings | McMaster-Carr

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43 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.

Hot-Dipped Galvanized Steel—Combines the strength of steel with the rust resistance of stainless steel. These nuts are an economical alternative to 18-8 stainless steel in wet and outdoor environments, but they won't hold up to salt water and chemicals. Use with other hot-dipped galvanized fasteners to ensure the threads mate tightly.

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



		7/8"-9	2 1/2"	1 1/4"	Fully Threaded	—	90264A250	00000	00000	00000


		7/8"-9	7"	1 3/8"	Partially Threaded	3 3/8"	90264A253	00000	00000	00000


		Black-Oxide Steel



				7/8"-9	2 1/4"	1 7/16"	Fully Threaded	—	91034A135	00000	00000	0000


				7/8"-9	2 1/2"	1 1/4"	Fully Threaded	—	91034A419	00000	00000	00000


				Hot-Dipped Galvanized Steel



						7/8"-9	2 1/2"	1 1/4"	Fully Threaded	—	93350A037	00000	00000	0000

Medium-Strength Steel

These Grade 5 or Class 8 nuts are about twice as strong as low-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.

							Each
	Thread Size	Lg.	Wd.	Fastener Strength Grade/Class	Threading		1-9	10-49	50-Up
Zinc-Plated Steel



		7/8"-9	2 1/2"	1 1/4"	SAE Grade 5	Fully Threaded	90977A037	000000	000000	000000

High-Strength Steel

Rated Grade 8 or Class 10, these are about 25% stronger than 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.

							Each
	Thread Size	Lg.	Wd.	Fastener Strength Grade/Class	Threading		1-9	10-49	50-Up
Zinc-Plated Steel



		7/8"-9	2 1/2"	1 5/16"	SAE Grade 8	Fully Threaded	90983A234	000000	000000	000000

Extreme-Strength Steel

Made from Grade 2H steel, these are about 20% stronger than high-strength steel coupling nuts. Use them with threaded rods that have a comparable strength rating to avoid stripping threads during installation.

Steel—Best for dry environments since moisture will cause these nuts to rust.

							Each
	Thread Size	Lg.	Wd.	Fastener Strength Grade/Class	Threading		1-9	10-49	50-Up
Steel



		7/8"-9	2 1/2"	1 1/2"	ASTM Grade 2H	Fully Threaded	90654A334	000000	000000	000000

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.

Highly Corrosion-Resistant 316 Stainless Steel—The most corrosion-resistant stainless steel coupling nuts we offer, these hold up in just about any environment. They won't degrade from exposure to weather, salt water, and most chemicals.

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



		7/8"-9	2 1/2"	1 1/4"	Fully Threaded	90268A037	000000	000000	000000


		Highly Corrosion-Resistant 316 Stainless Steel



				7/8"-9	2 1/2"	1 1/4"	Fully Threaded	90104A037	00000	00000	00000

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.	Wd.	Threading		1-9	10-49	50-Up
6061 Aluminum



		7/8"-9	2 1/2"	1 1/4"	Fully Threaded	90012A130	000000	000000	000000

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.

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

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



		7/8"-9	2 1/2"	1 1/4"	Fully Threaded	90465A327	000000	000000	000000

Inch-to-Inch Female Hex Thread Adapters

Connect two differently sized male-threaded parts, such as threaded rods, and tighten with a standard wrench. The threads on these adapters have various sizes and spacing, so you can increase or decrease thread size or adapt from coarse to fine threading. You can also use them to change the gender of a connection from male to female. Small adapters can work as threaded standoffs, which position and separate circuit boards and other components in assemblies.

Zinc-Plated Steel—Zinc-plated steel adapters resist corrosion until the plating wears away and are often used in dry environments.

18-8 Stainless Steel—18-8 stainless steel adapters withstand wet environments but will corrode when exposed to salt water and other chloride solutions.

316 Stainless Steel—316 stainless steel adapters are ideal in wet environments and will not corrode when exposed to salt water or harsh chemicals.

ASTM A108, ASTM A276, ASTM A582, and ASTM B633—Adapters that meet ASTM specifications are made from or plated with materials that adhere to specific standards for chemical and physical properties, such as hardness.

			Thread Lg.		Thread Fit		Hex								Each
	Thread Size (A)	Thread Size (B)	(A)	(B)	(A)	(B)	Size	Length	Specs. Met	Tensile Strength, psi	Hardness	Certificate Form	Certificate Type		1-9	10-Up
Zinc-Plated Steel



		5/8"-11	7/8"-9	5/8"	3/4"	Unified Standard Class 2B	Unified Standard Class 2B	1 1/4"	1 3/4"	ASTM A108, ASTM B633	75,000	Rockwell B65	—	—	97088A235	00000	00000


		3/4"-10	7/8"-9	3/4"	3/4"	Unified Standard Class 2B	Unified Standard Class 2B	1 1/4"	1 3/4"	ASTM A108, ASTM B633	75,000	Rockwell B65	—	—	97088A240	0000	0000
		7/8"-9	1"-8	7/8"	1"	Unified Standard Class 2B	Unified Standard Class 2B	1 3/8"	2"	ASTM A108, ASTM B633	75,000	Rockwell B65	—	—	97088A301	0000	0000
		7/8"-9	1 1/4"-7	7/8"	1 1/16"	Unified Standard Class 2B	Unified Standard Class 2B	1 5/8"	3"	ASTM A108, ASTM B633	75,000	Rockwell B65	—	—	97088A320	00000	00000


		18-8 Stainless Steel



				5/8"-11	7/8"-9	5/8"	7/8"	Unified Standard Class 2B	Unified Standard Class 2B	1 1/4"	2"	ASTM A582	85,000	Rockwell B80	Digital	Material Certificate with Traceable Lot Number	98434A121	00000	00000


				3/4"-10	7/8"-9	3/4"	7/8"	Unified Standard Class 2B	Unified Standard Class 2B	1 1/4"	2 1/4"	ASTM A582	85,000	Rockwell B80	Digital	Material Certificate with Traceable Lot Number	98434A124	00000	00000
				7/8"-9	1"-8	7/8"	1"	Unified Standard Class 2B	Unified Standard Class 2B	1 3/8"	2"	ASTM A582	85,000	Rockwell B80	—	—	91072A188	00000	00000
				7/8"-9	1 1/4"-7	7/8"	1 1/16"	Unified Standard Class 2B	Unified Standard Class 2B	1 5/8"	3"	ASTM A582	85,000	Rockwell B80	—	Material Certificate with Traceable Lot Number	91072A189	00000	00000


				316 Stainless Steel



						5/8"-11	7/8"-9	5/8"	7/8"	Unified Standard Class 2B	Unified Standard Class 2B	1 1/4"	2"	ASTM A276	75,000	Rockwell B83	—	Material Certificate with Traceable Lot Number	91072A265	00000	00000


						3/4"-10	7/8"-9	3/4"	7/8"	Unified Standard Class 2B	Unified Standard Class 2B	1 1/4"	2 1/4"	ASTM A276	75,000	Rockwell B83	Digital	Material Certificate with Traceable Lot Number	91072A268	00000	00000
						7/8"-9	1"-8	7/8"	1"	Unified Standard Class 2B	Unified Standard Class 2B	1 3/8"	2"	ASTM A276	75,000	Rockwell B83	Digital	Material Certificate with Traceable Lot Number	91072A271	00000	00000

Left-Hand-Thread Coupling Nuts

Pair with left-hand threaded rods, and turn to the left to tighten. Also known as extension nuts, these are commonly used to connect lengths of threaded rod and join threaded parts.

Low-Strength Steel

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

						Each
	Thread Size	Lg.	Wd.	Threading		1-9	10-Up
Zinc-Plated Steel



		7/8"-9	2 1/2"	1 1/4"	Fully Threaded	93345A239	000000	000000

Left-Hand to Right-Hand Female Hex Thread Adapters

Often called sleeve nuts, these thread adapters fasten parts with right-hand threads to parts with left-hand threads.

Black-Oxide Steel—Choose black-oxide steel adapters to match the aesthetics of your system or for their mild corrosion resistance. The finish won't chip or rub off. They resist rust in indoor and dry environments, but avoid using them in corrosive environments.

Zinc-Plated Steel—Zinc-plated steel adapters are strong and corrosion resistant.

			Thread Lg.		Thread Fit		Hex				Each
	Thread Size (A)	Thread Size (B)	(A)	(B)	(A)	(B)	Size	Length	Hardness		1-9	10-Up
Black-Oxide Steel



		7/8"-9	7/8"-9	1 1/2"	1 1/2"	Unified Standard Class 2B	Unified Standard Class 2B	1 3/8"	5"	Rockwell B80	91998A118	000000	000000


		Zinc-Plated Steel



				7/8"-9	7/8"-9	3 1/4"	3 1/4"	Unified Standard Class 2B	Unified Standard Class 2B	1 3/8"	7"	Rockwell B65	94280A131	00000	00000

Pipe Expansion Joints with Flanged Ends

Shown Installed on a Flanged Pipe

These joints reduce stress, vibration, and noise in piping systems by providing a point of flexibility to absorb movement. The flanged ends rotate for easy bolt hole alignment during installation. They mate with a same-size flat-surface Class 150 flange without the need for a gasket. Joints have a flexible body that is reinforced with nylon for added strength.

Position the expansion joints as close as possible to anchor points.

Neoprene


Expansion Joint	Limit Rod

Limit Rod Sets—Attach limit rod sets (sold separately) to the flanges to prevent overextension where anchoring is insufficient. To accommodate the thickness of the limit rod mounting plate, use bolts that are _7/8" longer than the bolts connecting the expansion joint to the pipe flange. Each set of limit rods requires eight bolts (not included).

Pipe Expansion Joints																	Limit Rod Sets
				Distance										Threaded Bolt Holes
Flange OD	Pipe Size	Lg.	No. of Bolt Holes	Compression	Expansion	Offset	Max. Pressure @ Temp.	Expansion Joint Type	Flange Material	Reinforcement Material	For Use With	Temp. Range, ° F	Max. Vacuum @ Temp.	Bolt Hole Thread Size		Each		Pair
16"	10	8"	12	1"	5/8"	3/4"	220 psi @ 72° F	Single Bulb	Zinc-Plated Steel	Nylon	Nonabrasive Slurries, Water	-10 to 220	26 in. Hg @ 72° F	7/8"-9	9175K21	0000000	9175K91	0000000
19"	12	8"	12	1"	5/8"	3/4"	220 psi @ 72° F	Single Bulb	Zinc-Plated Steel	Nylon	Nonabrasive Slurries, Water	-10 to 220	26 in. Hg @ 72° F	7/8"-9	9175K22	000000	9175K92	000000

Pipe Expansion Joints with Flanged Ends for High Vibration

Shown Installed on a Flanged Pipe

These expansion joints have a double-bulb design for extra movement and vibration absorption. The flanged ends rotate for easy bolt hole alignment during installation. They mate with a same-size flat-surface Class 150 flange without the need for a gasket. Joints have a flexible body that is reinforced with nylon for added strength.

Neoprene


Expansion Joint	Limit Rod

Pipe Expansion Joints																	Limit Rod Sets
				Distance										Threaded Bolt Holes
Flange OD	Pipe Size	Lg.	No. of Bolt Holes	Compression	Expansion	Offset	Max. Pressure @ Temp.	Expansion Joint Type	Flange Material	Reinforcement Material	For Use With	Temp. Range, ° F	Max. Vacuum @ Temp.	Bolt Hole Thread Size		Each		Pair
16"	10	13"	12	2 3/8"	1 3/8"	1 3/8"	220 psi @ 72° F	Double Bulb	Zinc-Plated Steel	Nylon	Grain Alcohol, Nonabrasive Slurries, Water	-10 to 220	26 in. Hg @ 72° F	7/8"-9	6819K69	0000000	6819K92	0000000
19"	12	13"	12	2 3/8"	1 3/8"	1 3/8"	220 psi @ 72° F	Double Bulb	Zinc-Plated Steel	Nylon	Grain Alcohol, Nonabrasive Slurries, Water	-10 to 220	26 in. Hg @ 72° F	7/8"-9	6819K71	00000000	6819K93	000000

Corrosion-Resistant Fully Threaded Rod End Bolts

304 Stainless Steel

Image of Attribute. Front orientation. Contains Annotated, MultipleImages. Corrosion-Resistant Fully Threaded Rod End Bolts.

These rod end bolts are good for wet and corrosive environments—for maximum mounting flexibility, cut the fully threaded shaft to whatever length you need. Also known as swing bolts and eyebolts, rod end bolts have no moving parts. They're designed to make pivoting or hinge movements in applications that don't need to compensate for misalignment.

304 Stainless Steel—303 and 304 stainless steel rod end bolts won't rust in humid, wet, and washdown environments. They're stronger than brass bolts and nearly as strong as steel. They will rust when exposed to salt water and chemicals, however.

ASTM A193—ASTM rod end bolts meet a standard for material.

	Shank
	Thread Size	Ctr. Lg.	Thread Lg.	ID	Overall Wd.	Shank Threading	Overall Thk.	Tensile Strength, psi	Specs. Met	Fastener Strength Grade/Class		Each
Right-Hand Shank Thread







				304 Stainless Steel

				7/8"-9	5"	3 13/16"	7/8"	1 7/8"	Fully Threaded	7/8"	75,000	ASTM A193	ASTM Grade B8	2434K44	000000


				7/8"-9	6"	4 13/16"	7/8"	1 7/8"	Fully Threaded	7/8"	75,000	ASTM A193	ASTM Grade B8	2434K33	00000

Fully Threaded Rod End Bolts

For maximum mounting flexibility, cut the fully threaded shaft to whatever length you need. Also known as swing bolts and eyebolts, rod end bolts have no moving parts. They're designed to make pivoting or hinge movements in applications that don't need to compensate for misalignment.

	Shank
	Thread Size	Ctr. Lg.	Thread Lg.	ID	Overall Wd.	Shank Threading	Overall Thk.	Tensile Strength	Specs. Met		Each
Right-Hand Shank Thread







				Black-Oxide Carbon Steel

				7/8"-9	5"	3 13/16"	7/8"	1 7/8"	Fully Threaded	7/8"	Not Rated	ASTM A521 Grade CA	3798K45	000000


				7/8"-9	6"	4 13/16"	7/8"	1 7/8"	Fully Threaded	7/8"	Not Rated	ASTM A521 Grade CA	3798K33	00000

High-Strength Fully Threaded Rod End Bolts

These alloy steel rod end bolts have the highest tensile strength of any steel fully threaded rod end bolt we offer. For maximum mounting flexibility, cut the fully threaded shaft to whatever length you need. Also known as swing bolts and eyebolts, rod end bolts have no moving parts. They're designed to make pivoting or hinge movements in applications that don't need to compensate for misalignment.

	Shank
	Thread Size	Ctr. Lg.	Thread Lg.	ID	Overall Wd.	Shank Threading	Overall Thk.	Tensile Strength, psi	Specs. Met	Fastener Strength Grade/Class		Each
Right-Hand Shank Thread







				Black-Oxide Alloy Steel

				7/8"-9	5"	3 13/16"	7/8"	1 7/8"	Fully Threaded	7/8"	125,000	ASTM A193	ASTM Grade B7	2440K45	000000


				7/8"-9	6"	4 13/16"	7/8"	1 7/8"	Fully Threaded	7/8"	125,000	ASTM A193	ASTM Grade B7	2440K33	00000

Partially Threaded Rod End Bolts

Create pivoting connections in applications that require high shear strength—the partially threaded shank of these rod end bolts withstands more side force than a fully threaded shank. Also known as swing bolts and eyebolts, they are used to create hinges, turnbuckles, and tie downs. Unlike ball joint rod ends, these rod end bolts are made from a single piece of metal, so they wear down more slowly and have a more controlled swing. However, because they do not have a moving ball joint, they do not compensate for angular misalignment. Made from steel, they are stronger and more wear resistant than stainless steel rod end bolts, but they are not as corrosion resistant.

Black-Oxide Carbon Steel—Rod end bolts with a black-oxide finish have a dark, matte coating that keeps the steel from rusting in dry environments.

	Shank
	Thread Size	Ctr. Lg.	Thread Lg.	ID	Overall Wd.	Shank Threading	Overall Thk.	Tensile Strength, psi		Each
Right-Hand Shank Thread







				Black-Oxide Carbon Steel

				7/8"-9	6"	2"	3/4"	1 3/4"	Partially Threaded	15/16"	75,000	6066K61	000000


				7/8"-9	12"	4"	3/4"	1 3/4"	Partially Threaded	15/16"	75,000	6066K62	00000
				7/8"-9	6"	2"	7/8"	1 3/4"	Partially Threaded	15/16"	75,000	6066K72	00000