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What is Coupling Nut? Properties, Dimensions and Uses

What are Coupling Nut

If you’re building, installing, or manufacturing equipment, you already know about coupling nuts. But if you don’t, don’t worry – we’re here to help. This blog post will cover what coupling nuts are and how they can be used in various applications.

What are Coupling Nuts?

Coupling nuts are hexagonal-shaped fasteners that consist of two threaded ends. They are typically used to join two pieces of the threaded rod together, allowing them to extend beyond the length of a single piece. The two ends are often different, making joining two pieces with varying thread sizes easier. The most common sizes for coupling nuts range from 1/4″ to 1″, but larger sizes may also be available.

How Are Coupling Nuts Used?

Coupling nuts are used in many industries such as construction, engineering and manufacturing because they provide an easy way to combine two pieces of the threaded rod. This makes them incredibly useful when connecting pipes or other materials that require a secure fit. For example, they can be used in plumbing installations where two pipes must be connected without any gap or slack for the connection to hold firmly. They can also be used for hanging fixtures such as curtain rods or shower curtains when traditional screws or anchors won’t do the trick.

What Are the Benefits of Using Coupling Nuts?

Aside from their versatility, coupling nuts have several benefits over traditional fasteners such as screws or bolts:

  • They require no special tools to install; all that is needed is a wrench or socket set, depending on the size of the nut being installed.
  • They provide a secure connection since both sides have threads that interlock when tightened correctly.
  • Since the threads on both sides match up perfectly when installed correctly, there is no risk of any gaps forming, which could cause leaks within your system down the line.

Coupling Nut Properties

  • Coupling nuts connect two pieces of threaded rod or other components.
  • Coupling nuts are available in a variety of sizes and materials.
  • The most common material for coupling nuts is carbon steel, but they are also available in stainless steel, brass, and nylon.
  • Coupling nuts must be tightened with a wrench to ensure a secure connection.
  • Coupling nuts are often used when frequent disassembly and assembly are required, such as in plumbing and electrical applications.

Coupling Nut Dimensions

Nominal
Size
Basic
Major
Diameter
of
Thread
F G H
Width
Across
Flats
Width
Across
Corners
Thickness
Hex
Nut
basic min max. min. max. basic min. max.
#6 0.138 5/16 0.302 0.312 0.344 0.361 1/2 0.470 0.510
#8 0.164 5/16 0.302 0.312 0.344 0.361 5/8 0.595 0.645
#10 0.190 5/16 0.302 0.312 0.344 0.361 3/4 0.711 0.760
1/4 0.250 7/16 0.428 0.438 0.488 0.505 1 3/4 1.690 1.760
5/16 0.312 1/2 0.489 0.500 0.557 0.577 1 3/4 1.690 1.760
3/8 0.375 9/16 0.551 0.562 0.628 0.650 1 3/4 1.690 1.760
7/16 0.437 5/8 0.607 0.625 0.692 0.722 1 3/4 1.690 1.760
1/2 0.500 11/16 0.663 0.688 0.756 0.794 1 3/4 1.690 1.760
9/16 0.562 13/16 0.782 0.813 0.891 0.939 2 1/8 2.067 2.135
5/8 0.625 13/16 0.782 0.813 0.891 0.939 2 1/8 2.067 2.135
3/4 0.750 1 0.963 1.000 1.097 1.155 2 1/4 2.190 2.260
7/8 0.875 1 1/4 1.212 1.250 1.382 1.443 2 1/2 2.440 2.510
1 1.000 1 3/8 1.325 1.375 1.511 1.588 2 3/4 2.690 2.760
Nominal
Size
Basic
Major
Diameter
of
Thread
F G H
Width
Across
Flats
Width
Across
Corners
Thickness
Hex
Nut
basic min max. min. max. basic min. max.
1 1/8 1.125 1 1/2 1.450 1.500 1.653 1.732 3 2.940 3.010
1 1/4 1.250 1 5/8 1.575 1.625 1.825 1.876 3 2.940 3.010
1 1/2 1.500 2 1.950 2.000 2.275 2.309 3 1/2 3.440 3.510
1 5/8 1.625 2 9/16 2.481 2.562 2.828 2.959 4 7/8 4.830 4.910
1 3/4 1.750 2 3/4 2.662 2.750 3.035 3.175 5 1/4 5.210 5.290
1 7/8 1.875 2 15/16 2.844 2.938 3.242 3.392 5 5/8 5.580 5.670
2 2.000 3 1/8 3.025 3.125 3.448 3.608 6 5.950 6.040
2 1/4 2.250 3 1/2 3.388 3.500 3.862 4.041 6 3/4 6.700 6.800
2 1/2 2.500 3 7/8 3.750 3.875 4.275 4.474 7 1/2 7.440 7.550
2 3/4 2.750 4 1/4 4.112 4.250 4.688 4.907 8 1/4 8.190 8.310
3 3.000 4.5/8 4.475 4.625 5.101 5.340 9 8.940 9.060
Nominal
Size
Basic
Major
Diameter
of
Thread
F G H
Width
Across
Flats
Width
Across
Corners
Thickness
Hex
Nut
basic min max. min. max. basic min. max.
3 1/4 3.250 5 4.838 5.000 5.515 5.773 9 3/4 9.680 9.810
3 1/2 3.500 5 3/8 5.200 5.375 5.928 6.206 10 1/2 10.430 10.570
3 3/4 3.750 5 3/4 5.562 5.750 6.340 6.639 11 1/4 11.170 11.320
4 4.000 6 1/8 5.925 6.125 6.754 7.072 12 11.920 12.080
4 1/4 4.250 6 1/2 6.288 6.500 7.168 7.506 12 3/4 12.670 12.830
4 1/2 4.500 6 7/8 6.650 6.875 7.581 7.939 13 1/2 13.420 13.580
4 3/4 4.750 7 1/4 7.012 7.250 7.994 8.372 14 1/4 14.160 14.340
5 5.000 7 5/8 7.375 7.625 8.408 8.805 15 14.910 15.090
5 1/4 5.250 8 7.738 8.000 8.821 9.238 15 3/4 15.650 15.850
5 1/2 5.500 8 3/8 8.100 8.375 9.234 9.671 16 1/2 16.400 16.600
5 3/4 5.750 8 3/4 8.462 8.750 9.647 10.104 17 1/4 17.150 17.350
6 6.000 9 1/8 8.825 9.125 10.060 10.537 18 17.890 18.110

Conclusion:

Coupling nuts are essential for many industrial applications due to their ease of use and secure connection capabilities. They provide an efficient way to join two pieces of the threaded rod together while allowing for a tight seal between materials when installed correctly. While they may only be suitable for some applications involving threaded rods due to their limited size range, coupling nuts remain one of the most reliable and cost-effective options today for securely connecting pipes without having to use additional tools or materials during installation. DIYers and engineers alike should consider using coupling nuts whenever possible!

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