Steel Hex Nut Info
USS & SAE – Overview & Specifications
A563 Nuts
A563 hex nuts are a standardized category of carbon and alloy steel nuts defined by ASTM A563, used primarily with externally threaded fasteners like bolts and studs in structural and industrial applications. These nuts come in various grades (such as A, C, DH, and DH3), each with different strength levels and mechanical properties to match the requirements of the mating bolts, such as A325 or A490 structural bolts. A563 nuts are available in both standard and heavy hex dimensions, with heavy hex nuts providing a larger bearing surface and higher strength. They are commonly used in steel construction, bridges, heavy equipment, and infrastructure projects. Finishes can include plain, zinc-coated, or hot-dip galvanized to suit different environmental and corrosion-resistance needs.
A563 heavy hex nuts, which are commonly used with high-strength bolts in structural and industrial applications. These heavy hex nuts are designed to offer increased strength and larger bearing surfaces compared to standard hex nuts, ensuring a more secure fit and better load distribution.
Nut Size (Inches) | Width Across Flats (WAF) | Height (H) | Inner Diameter (ID) | Thickness |
|---|---|---|---|---|
1/2″ | 0.875″ | 0.500″ | 0.531″ | 0.250″ |
5/8″ | 1.000″ | 0.562″ | 0.656″ | 0.312″ |
3/4″ | 1.125″ | 0.625″ | 0.750″ | 0.375″ |
7/8″ | 1.250″ | 0.750″ | 0.875″ | 0.375″ |
1″ | 1.375″ | 0.875″ | 1.062″ | 0.437″ |
1-1/4″ | 1.625″ | 1.000″ | 1.281″ | 0.500″ |
1-1/2″ | 1.750″ | 1.125″ | 1.500″ | 0.562″ |
1-3/4″ | 1.875″ | 1.250″ | 1.750″ | 0.625″ |
2″ | 2.000″ | 1.375″ | 2.062″ | 0.625″ |
A563 heavy hex nuts are designed for use in high-strength applications where larger load-bearing capacity and strength are necessary. The thicker design and larger dimensions allow for better performance in structural steel, bridges, machinery, and other critical infrastructure projects. These nuts are commonly paired with high-strength bolts like A325 and A490 to create secure, long-lasting connections.
2H Nuts
2H nuts are heavy hex nuts made from high-strength, heat-treated carbon or alloy steel, conforming to ASTM A194 Grade 2H specifications. These nuts are specifically designed for use in high-pressure and high-temperature applications, commonly found in the petrochemical, power generation, and structural industries. The “heavy hex” designation means they are larger and thicker than standard hex nuts, providing greater strength and load-bearing capability. 2H nuts are typically paired with high-strength bolts such as A325, A490, or B7 studs in flanged, bolted connections, especially in pressure vessels, valves, and piping systems. They are often available in plain, black oxide, or galvanized finishes for corrosion protection depending on the service environment.
2H nuts, which are heavy hex nuts made from high-strength, heat-treated carbon or alloy steel, typically used in high-pressure, high-temperature applications. These dimensions are commonly specified for 2H nuts and follow the ASTM A194 Grade 2H standards.
Nut Size (Inches) | Width Across Flats (WAF) | Height (H) | Inner Diameter (ID) | Thickness |
|---|---|---|---|---|
1/2″ | 0.875″ | 0.437″ | 0.531″ | 0.312″ |
5/8″ | 1.000″ | 0.500″ | 0.656″ | 0.375″ |
3/4″ | 1.125″ | 0.625″ | 0.750″ | 0.375″ |
7/8″ | 1.250″ | 0.750″ | 0.875″ | 0.437″ |
1″ | 1.375″ | 0.875″ | 1.062″ | 0.437″ |
1-1/4″ | 1.625″ | 1.000″ | 1.281″ | 0.500″ |
1-1/2″ | 1.750″ | 1.125″ | 1.500″ | 0.500″ |
1-3/4″ | 1.875″ | 1.250″ | 1.750″ | 0.562″ |
2″ | 2.000″ | 1.375″ | 2.062″ | 0.562″ |
2H nuts are designed to withstand high mechanical stresses and high-temperature environments, which makes them suitable for applications such as pressure vessels, heavy-duty machinery, and large structural components. The thickness and height of 2H nuts are generally greater than standard hex nuts, ensuring better strength and performance in demanding conditions.
Low Carbon Nuts
Low carbon hex nuts are six-sided nuts made from low carbon steel, a material known for its ductility, weldability, and cost-effectiveness. These nuts are typically used in general-purpose, non-critical applications where high strength is not required. Commonly paired with low carbon bolts or threaded rods, they are ideal for use in construction, light machinery, furniture assembly, and other basic fastening tasks. Due to their relatively soft composition, low carbon hex nuts are easy to machine and install but are not suitable for high-stress or high-temperature environments. They often come in plain or zinc-plated finishes to offer some resistance to corrosion.
Standard dimensions for low carbon hex nuts. These nuts are commonly used in general-purpose, non-critical applications where high strength is not necessary.
Nut Size (Inches) | Width Across Flats (WAF) | Height (H) | Inner Diameter (ID) | Thickness |
|---|---|---|---|---|
1/2″ | 0.750″ | 0.375″ | 0.531″ | 0.062″ |
5/8″ | 0.875″ | 0.438″ | 0.656″ | 0.062″ |
3/4″ | 1.000″ | 0.500″ | 0.750″ | 0.062″ |
7/8″ | 1.125″ | 0.563″ | 0.875″ | 0.062″ |
1″ | 1.250″ | 0.625″ | 1.062″ | 0.062″ |
1-1/4″ | 1.500″ | 0.750″ | 1.281″ | 0.093″ |
1-1/2″ | 1.750″ | 0.875″ | 1.500″ | 0.093″ |
1-3/4″ | 1.875″ | 1.000″ | 1.750″ | 0.093″ |
2″ | 2.000″ | 1.125″ | 2.062″ | 0.093″ |
These dimensions are based on standard low-carbon hex nuts and are suitable for light-duty applications. The width across flats (WAF) is the distance across the nut’s flat surfaces, used for wrench sizing. The thickness and height are standard values for most general-use nuts, providing adequate thread engagement and strength for many everyday applications.
Jam Nuts
Jam nuts or leveling nuts are thin hex nuts typically used as a locking mechanism to prevent another nut from loosening due to vibration or movement. They are about half the thickness of a standard hex nut and are often used in pairs—either with a standard nut or another jam nut—on the same bolt or threaded rod. By tightening the jam nut against the main nut, friction is created that helps lock both nuts in place, reducing the likelihood of loosening. Jam nuts are commonly used in machinery, automotive assemblies, and threaded rod applications where space is limited and a reliable locking method is needed without using additional hardware like lock washers or thread-locking compounds.
Hot-dip Galvanizing
Hot-dip galvanizing is a corrosion protection process in which steel components are dipped into molten zinc, forming a metallurgically bonded zinc coating. This zinc layer acts as a physical barrier, preventing moisture and oxygen from reaching the steel surface, and also offers sacrificial protection—meaning the zinc corrodes in place of the steel. As a result, galvanized steel can resist rust and corrosion for decades, even in harsh outdoor or marine environments. Common uses of hot-dip galvanized steel include structural steel frameworks, utility poles, guardrails, fasteners, and agricultural or marine equipment. Its durability and low maintenance make it a preferred choice for long-term, corrosion-resistant applications.