7/8"-9 Standoffs | McMaster-Carr

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26 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-Up
Zinc-Plated Steel



		7/8"-9	2 1/2"	1 1/4"	Fully Threaded	—	000000000	00000	00000


		7/8"-9	7"	1 3/8"	Partially Threaded	3 3/8"	000000000	00000	00000


		Black-Oxide Steel



				7/8"-9	2 1/4"	1 7/16"	Fully Threaded	—	000000000	00000	00000


				7/8"-9	2 1/2"	1 1/4"	Fully Threaded	—	000000000	00000	00000


				Hot-Dipped Galvanized Steel



						7/8"-9	2 1/2"	1 1/4"	Fully Threaded	—	000000000	00000	00000

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-Up
Zinc-Plated Steel



		7/8"-9	2 1/2"	1 1/4"	SAE Grade 5	Fully Threaded	000000000	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-Up
Zinc-Plated Steel



		7/8"-9	2 1/2"	1 5/16"	SAE Grade 8	Fully Threaded	000000000	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-Up
Steel



		7/8"-9	2 1/2"	1 1/2"	ASTM Grade 2H	Fully Threaded	000000000	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-Up
18-8 Stainless Steel



		7/8"-9	2 1/2"	1 1/4"	Fully Threaded	000000000	000000	000000


		Highly-Corrosion-Resistant 316 Stainless Steel



				7/8"-9	2 1/2"	1 1/4"	Fully Threaded	000000000	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-Up
6061 Aluminum



		7/8"-9	2 1/2"	1 1/4"	Fully Threaded	000000000	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.

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



		7/8"-9	2 1/2"	1 1/4"	Fully Threaded	000000000	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		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	000000000	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	000000000	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	000000000	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	000000000	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	000000000	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	000000000	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	000000000	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	000000000	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	000000000	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	000000000	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	000000000	00000	00000

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	000000000	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	000000000	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	000000000	000000	000000