1 1/4"-12 Couplings | McMaster-Carr

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	System of Measurement System of Measurement

Inch

	Thread Size Thread Size	Show

1 1/4"-12

	Thread Size Thread Size	Hide

	Nut Type Nut Type


Coupling	Hex

	Width Width

1 5/8"

1 7/8"

	Length Length

	Fastener Strength Grade/Class Fastener Strength Grade/Class

	Grade 8

	Material Material

Brass

Steel

	Finish Finish

Zinc Plated

	Thread Spacing Thread Spacing

Fine

	Threading Threading

	Fully Threaded

	Body Material Body Material

Steel

Stainless Steel

	Thread Direction Thread Direction

Right Hand

Left Hand

	Thread Type Thread Type

	OD OD

2 1/2"

3 1/2"

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

DFARS Specialty Metals
COTS-Exempt

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

RoHS Compliant

RoHS Compliant with
Exemptions

	Drive Style Drive Style

	External Hex

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

REACH Compliant

	Angle of Misalignment Angle of Misalignment

2°

5°

	Coupling Nut Profile Coupling Nut Profile

Standard

	Maximum Pull Force Maximum Pull Force

10,000 to 19,999 lbs.

40,000 to 99,999 lbs.

100,000 lbs. or greater

	For Tube OD For Tube OD

7/8"

	Thread Fit Thread Fit

Class 2B

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How to Identify and Measure Fittings

Pipe size is an industry designation, not the actual size. View information about how to measure threaded and unthreaded pipe and pipe fittings.

About Air Cylinders

About Nuts, Materials, and Finishes

Nuts for Barbed Hose Fittings for Compressed Gas

Also known as CGA (Compressed Gas Association) nuts, these are designed for low-pressure welding applications downstream of your tank and pressure regulator. Slide a barbed hose adapter for compressed gas into a male or female nut to make a threaded connection to torches or pressure regulators.

Nuts with left-hand threads are identified with a notch.

Brass nuts have good corrosion resistance. Note: Nuts have a CGA number that corresponds to a specific type of gas. Choose a nut with the same CGA number as your tank and other system components.

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

Female

Maximum Pressure: 200 psi @ 72° F
Maximum Temperature: 120° F

Brass
CGA Number	Gas Fitting Size	Thread Size	Thread Type	Thread Direction	For Use With		Each
026	D	1 1/4"-12	UN/UNF (CGA)	Right Hand	Oxygen	000000000	000000
027	D	1 1/4"-12	UN/UNF (CGA)	Left Hand	Acetylene, Butane, Fuel Gases, LP Gas, Natural Gas, Propane	000000000	00000

45° Flared Fittings for Copper and Brass Tubing

Temperature Range: -65° to 250° F
Tubing: Use with seamless brass and copper that meets ASTM B280
Specifications Met: SAE J512, SAE J513, UL Listed, except socket-connect fittings and fittings with BSPT thread meet SAE J512 and SAE J513 only

No sleeve is required to assemble these fittings, which makes for a faster, more convenient installation compared to 37° flared fittings. They require a nut (sold separately) for each tube end. Fittings are also known as refrigeration and SAE fittings. They are brass for good corrosion resistance.

NPTF (Dryseal) threads are compatible with NPT threads.

Copper tube size is the accepted designation of the copper tubing industry, not the actual tube OD.

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

Straight Adapters, Tube × Male Threaded Pipe

For Use With:
NPTF Threads: Air, Cutting Oil, Diesel Fuel, Fuel Oil, Mineral Oil, Refrigerant, Water
BSPT Threads: Air, Cutting Oil, Diesel Fuel, Mineral Oil, Refrigerant, Water

For Tube
OD	Wall Thick.	Pipe Size	Material	Max. Pressure		Each
NPTF Threads
7/8"	0.045"	3/4	Brass	450 psi @ 72° F	00000000	000000

Nuts

(A) Short Nut

For Use With: Air, Cutting Oil, Diesel Fuel, Fuel Oil, Mineral Oil, Refrigerant, Water

	For Tube
	OD	Wall Thick.	Nut Material	Max. Pressure	Lg.		Each
Short Nuts
A	7/8"	Not Rated	Brass	450 psi @ 72° F	1 5/8"	00000000	000000

Nuts for 45° Flared Fittings for Copper and Brass Tubing

(A) Short Nut

For Use With: Cutting Oil, Fuel Oil, Refrigerant, Mineral Oil, Diesel Fuel, Water, Air
Temperature Range: -65° to 250° F
Tubing: Use with seamless brass and copper that meets ASTM B280
Specifications Met: SAE J512, SAE J513, UL Listed

Use these nuts with 45° flared tube fittings to provide a tight metal-to-metal seal on flared copper and brass tubing. Nuts are brass for good corrosion resistance. They don’t require a sleeve, which makes for a fast, convenient installation.

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

	For Tube
	OD	Wall Thick.	Nut Material	Max. Pressure	Lg.		Each
Short Nuts
A	7/8"	Not Rated	Brass	450 psi @ 72° F	1 5/8"	00000000	000000

Low-Strength Steel Coupling Nuts

Also known as extension nuts, use these to connect and extend threaded rods. They're about half the strength of medium-strength steel coupling nuts for use in light duty fastening applications.

Zinc-plated steel coupling nuts resist corrosion in wet environments.

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

				Each
Thread Size	Lg.	Wd.		1-9	10-Up
Zinc-Plated Steel
1 1/4"-12	3"	1 5/8"	000000000	000000	000000

High-Strength Steel Coupling Nuts—Grade 8

Also known as extension nuts, use these to connect and extend threaded rods. Made from Grade 8 steel, they're about 25% stronger than medium-strength steel coupling nuts. A zinc plating provides corrosion resistance in wet environments.

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

				Each
Thread Size	Lg.	Wd.		1-9	10-Up
Zinc-Plated Steel—Grade 8
1 1/4"-12	3"	1 7/8"	000000000	000000	000000

Rod Alignment Couplers

Increase cylinder life by fixing alignment problems between air or hydraulic cylinders and driven components. Couplers have a threaded end that moves to compensate for the angle of misalignment, reducing wear on cylinder bearings and seals. Couplers have a male and female end.

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

Inch Sizes

Angle of Misalignment

2° of Misalignment
Thread Size	Body Material	OD	Lg.	Max. Pull Force, lbs.		Each
1 1/4"-12	303 Stainless Steel	2 1/2"	4 7/16"	19,500	0000000	0000000
1 1/4"-12	Steel	2 1/2"	4 7/16"	78,000	0000000	000000
5° of Misalignment
1 1/4"-12	Steel	3 1/2"	6"	123,300	000000	000000

Hitch Balls

Mount these onto a hitch insert, and connect them to a trailer with a hitch-ball coupler. Maximum trailer weight is the total weight being towed.

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

Chrome-Plated Steel
For Max. Trailer Wt., lbs.	Hitch Ball Dia.	Thread Size	Stud Lg.		Each
10,000	2 5/16"	1 1/4"-12	2 1/8"	000000	000000