Hex nuts are integral components in a variety of applications, providing essential fastening capabilities that ensure the stability and security of assembled parts. By understanding the different types and dimensions of hex nuts with size charts in different units (mm & inches), users can ensure the performance of hex nuts for daily life and complex machinery.
What Is a Hex Nut?
A hex nut is a type of fastener characterized by its hexagonal shape, which features six sides, it is easy to grip and turn with standard tools like wrenches and sockets. Hex nuts have internal threading that allows them to be screwed onto a bolt or screw, securing multiple parts together. Hex nuts are found in countless applications, from assembling furniture and building structures to securing machinery and automotive parts.
Types of Hex Nuts
Hex nuts can be classified based on various elements, including thickness, material, and specific applications. Here are the different types of hex nuts.
1. Thickness
- Type I Hex Nuts: These are the most commonly used hex nuts, characterized by a nominal height (m) that is greater than or equal to 0.8 times the diameter (D) of the nut. They are further divided into grades A, B, and C based on precision and surface roughness requirements.
- Type II Hex Nuts: These nuts have a greater height than Type I nuts and are often used in applications where assembly and disassembly are frequent. They can be produced without heat treatment, making them more cost-effective for certain specifications.
- Thin Hex Nuts: These nuts are designed to be thinner than standard hex nuts and are used in applications where space is limited or where weight savings are critical.
2. Material
- Carbon Steel Hex Nuts: Commonly used for general applications, these nuts are made from various grades of carbon steel.
- Stainless Steel Hex Nuts: Known for their corrosion resistance, these nuts are typically made from austenitic stainless steels, which contain higher amounts of chromium and nickel.
- Copper Hex Nuts: These are used in specific applications where electrical conductivity is important.
Iron Hex Nuts: Less common, these nuts are used in specific industrial applications.
3. Use
- Flange Nuts: These nuts have a wider base that distributes the load over a larger area, making them suitable for applications where a secure fit is necessary.
- Lock Nuts: Designed to prevent loosening under vibration, these nuts are used in applications where stability is critical.
- Embedded Nuts: These are used in applications where the nut is embedded into a material for a secure fit.
4. Pitch
- Standard Teeth: Regularly spaced threads for general use.
- Fine Teeth: Threads that are closer together, providing better adjustment and resistance to loosening.
- Very Fine Teeth: Used in applications requiring precise adjustments.
- Anti-Tooth: Designed to prevent loosening due to vibrations.
Hex Nut Dimensions
Hex nuts are available in both metric and imperial measurements, common metric hex nut sizes like M6 and M8, and imperial examples include 1/4” and 3/8”. Below are the hex nut dimension tables in different units.
- Width Across Flats (WAF): refers to the distance between two opposite flat sides of the hexagonal shape. These dimensions are essential for compatibility with corresponding bolts and ensuring proper fastening.
- Width Across Corners (WAC): the measurement from one corner of the hexagon to the opposite corner. This dimension is important for ensuring that tools fit properly when working with hex nuts.
Metric Hex Nut Size Chart (ISO 4032) – Hex Nut Dimensions in MM
| Nut Size | Thread Pitch |
Width Across Flats |
Width Across Corners |
Height of the Nut |
||
| max. | min. | min. | max. | min. | ||
| M1.6 | 0.35 | 3.20 | 3.02 | 3.41 | 1.30 | 1.05 |
| M2 | 0.4 | 4.00 | 3.82 | 4.32 | 1.60 | 1.35 |
| M2.5 | 0.45 | 5.00 | 4.82 | 5.45 | 2.00 | 1.75 |
| M3 | 0.5 | 5.50 | 5.32 | 6.01 | 2.40 | 2.15 |
| M3.5* | 0.6 | 6.00 | 5.82 | 6.58 | 2.80 | 2.55 |
| M4 | 0.7 | 7.00 | 6.78 | 7.66 | 3.2 | 2.9 |
| M5 | 0.8 | 8.00 | 7.78 | 8.79 | 4.7 | 4.4 |
| M6 | 1 | 10.00 | 9.78 | 11.05 | 5.2 | 4.9 |
| M8 | 1.25 | 13.00 | 12.73 | 14.38 | 6.80 | 6.44 |
| M10 | 1.5 | 16.00 | 15.73 | 17.77 | 8.40 | 8.04 |
| M12 | 1.75 | 18.00 | 17.73 | 20.03 | 10.80 | 10.37 |
| M14* | 2 | 21.00 | 20.67 | 23.36 | 12.8 | 12.1 |
| M16 | 2 | 24.00 | 23.67 | 26.75 | 14.8 | 14.1 |
| M18* | 2.5 | 27.00 | 26.16 | 29.56 | 15.8 | 15.1 |
| M20 | 2.5 | 30.00 | 29.16 | 32.95 | 18.0 | 16.9 |
| M22* | 2.5 | 34 | 33 | 37.29 | 19.4 | 18.1 |
| M24 | 3 | 36 | 35 | 39.55 | 21.5 | 20.2 |
| M27* | 3 | 41 | 40 | 45.2 | 23.8 | 22.5 |
| M30 | 3.5 | 46 | 45 | 50.85 | 25.6 | 24.3 |
| M33* | 3.5 | 50 | 49 | 55.37 | 28.7 | 27.4 |
| M36 | 4 | 55.0 | 53.8 | 60.79 | 31.0 | 29.4 |
| M39* | 4 | 60.0 | 58.8 | 66.44 | 33.4 | 31.8 |
| M42 | 4.5 | 65.0 | 63.1 | 71.3 | 34.0 | 32.4 |
| M45* | 4.5 | 70.0 | 68.1 | 76.95 | 36.0 | 34.4 |
| M48 | 5 | 75.0 | 73.1 | 82.6 | 38.0 | 36.4 |
| M52* | 5 | 80.0 | 78.1 | 88.25 | 42.0 | 40.4 |
| M56 | 5.5 | 85.0 | 82.8 | 93.56 | 45.0 | 43.4 |
| M60* | 5.5 | 90.0 | 87.8 | 99.21 | 48.0 | 46.4 |
| M64 | 6 | 95.0 | 92.8 | 104.86 | 51.0 | 49.1 |
Imperial Hex Nut Size Chart (ASME B18.2.2) – Hex Nut Dimensions in Inch
| Nominal Size |
Basic Major Diameter of Thread |
Width Across Flats |
Width Across Corners |
Thickness Hex Nut |
Thickness Jam Nut |
||||
| min | max. | min. | max. | min. | max. | min. | max. | ||
| 1/4 | 0.2500 | 0.428 | 0.438 | 0.488 | 0.505 | 0.212 | 0.226 | 0.150 | 0.163 |
| 5/16 | 0.3125 | 0.489 | 0.500 | 0.557 | 0.577 | 0.258 | 0.273 | 0.180 | 0.195 |
| 3/8 | 0.3750 | 0.551 | 0.563 | 0.628 | 0.650 | 0.320 | 0.337 | 0.210 | 0.227 |
| 7/16 | 0.4375 | 0.675 | 0.688 | 0.768 | 0.794 | 0.365 | 0.385 | 0.240 | 0.260 |
| 1/2 | 0.5000 | 0.736 | 0.750 | 0.840 | 0.866 | 0.427 | 0.448 | 0.302 | 0.323 |
| 9/16 | 0.5625 | 0.861 | 0.875 | 0.982 | 1.010 | 0.473 | 0.496 | 0.301 | 0.324 |
| 5/8 | 0.6250 | 0.922 | 0.938 | 1.051 | 1.083 | 0.535 | 0.559 | 0.363 | 0.387 |
| 3/4 | 0.7500 | 1.088 | 1.125 | 1.240 | 1.299 | 0.617 | 0.665 | 0.398 | 0.446 |
| 7/8 | 0.8750 | 1.269 | 1.312 | 1.447 | 1.516 | 0.724 | 0.776 | 0.458 | 0.510 |
| 1 | 1.0000 | 1.450 | 1.500 | 1.653 | 1.732 | 0.831 | 0.887 | 0.519 | 0.575 |
| 1 1/8 | 1.1250 | 1.631 | 1.688 | 1.859 | 1.949 | 0.939 | 0.999 | 0.579 | 0.639 |
| 1 1/4 | 1.2500 | 1.812 | 1.875 | 2.066 | 2.165 | 1.030 | 1.094 | 0.687 | 0.751 |
| 1 3/8 | 1.3750 | 1.994 | 2.062 | 2.273 | 2.382 | 1.138 | 1.206 | 0.747 | 0.815 |
| 1 1/2 | 1.5000 | 2.175 | 2.250 | 2.480 | 2.598 | 1.245 | 1.317 | 0.808 | 0.880 |
| 1 5/8 | 1.6250 | 2.35 | 2.43 | 2.679 | 2.805 | 1.364 | 1.416 | 0.868 | 0.944 |
| 1 3/4 | 1.7500 | 2.538 | 2.625 | 2.893 | 3.031 | 1.460 | 1.540 | 0.929 | 1.009 |
| 1 7/8 | 1.8750 | 2.722 | 2.813 | 3.103 | 3.247 | 1.567 | 1.651 | 0.989 | 1.073 |
| 2 | 2.0000 | 2.900 | 3.000 | 3.306 | 3.464 | 1.675 | 1.763 | 1.050 | 1.138 |
| 2 1/4 | 2.2500 | 3.263 | 3.375 | 3.719 | 3.897 | 1.890 | 1.986 | 1.155 | 1.267 |
| 2 1/2 | 2.5000 | 3.625 | 3.750 | 4.133 | 4.330 | 2.105 | 2.209 | 1.401 | 1.427 |
| 2 3/4 | 2.7500 | 3.988 | 4.125 | 4.546 | 4.763 | 2.319 | 2.431 | 1.522 | 1.556 |
| 3 | 3.0000 | 4.350 | 4.500 | 4.959 | 5.196 | 2.534 | 2.654 | 1.643 | 1.685 |
| 3 1/4 | 3.2500 | 4.713 | 4.875 | 5.373 | 5.629 | 2.749 | 2.877 | 1.748 | 1.814 |
| 3 1/2 | 3.5000 | 5.075 | 5.250 | 5.786 | 6.062 | 2.964 | 3.100 | 1.870 | 1.943 |
| 3 3/4 | 3.7500 | 5.438 | 5.625 | 6.199 | 6.495 | 3.178 | 3.322 | 1.990 | 2.072 |
| 4 | 4.0000 | 5.800 | 6.000 | 6.612 | 6.928 | 3.393 | 3.545 | 2.112 | 2.201 |
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