Large flat sides make these nuts easy to grip with a wrench and keep them from rotating in channels and square holes. Made from SAE Grade 5 steel, they're suitable for fastening most machinery and equipment.

Steel—Steel square nuts are best for dry environments, since moisture will cause them to rust.

Zinc-Plated Steel—Zinc-plated steel square nuts resist corrosion in wet environments.

Made of ISO Class 04 steel and about two-thirds the height of standard steel square nuts, these nuts are suitable for most low-clearance fastening applications. Also known as square jam nuts, they’re commonly jammed together to hold each other in place. Their flat, broad sides make them easy to grip with a wrench and keep them from rotating in channels and square holes. Compared to hex nuts, a greater area is in contact with the fastened surface.

Black-Oxide Steel—Black-oxide steel square nuts have a dark surface color and are mildly corrosion resistant in dry environments.

Zinc-Plated Steel—Zinc-plated steel square nuts resist corrosion in wet environments.

DIN 562—These nuts meet DIN 562, an international standard that signifies their material and dimensions are compatible with other products and tools.

These square nuts have good chemical resistance and may be mildly magnetic. Large flat sides make them easy to grip with a wrench and keep them from rotating in channels and square holes.

Two-thirds the height of typical square nuts and made of 18-8 stainless steel, these metric nuts are designed for use in low-clearance applications in humid, damp, and washdown environments. They’re often called square jam nuts because they can be jammed together to hold each other in place. They’re easily gripped with a wrench due to their flat, broad sides, which also prevent them from rotating in channels and square holes. Compared to hex nuts, a greater area is in contact with the fastened surface. And compared to steel nuts, they’re slightly less strong.

Black-Oxide 18-8 Stainless Steel—Black-oxide 18-8 stainless steel nuts have a dark surface color.

DIN 562—These nuts meet DIN 562, an international standard that signifies their material and dimensions are compatible with other products and tools.

These square nuts have excellent resistance to chemicals and salt water. Large flat sides make them easy to grip with a wrench and keep them from rotating in channels and square holes.

Unlike metal nuts, these carbon fiber square nuts won’t warp at extreme temperatures, making them ideal for heat treating and furnace fixtures. They are lightweight with an excellent strength-to-weight ratio and can be used for storage racks and shelving. Large flat sides make these nuts easy to grip with a wrench and keep them from rotating in channels and square holes.

These square nuts are corrosion resistant in wet environments, electrically conductive, and nonmagnetic. Large flat sides make them easy to grip with a wrench and keep them from rotating in channels and square holes.

These fiberglass square nuts are chemical resistant, nonconductive, and lightweight. Large flat sides make them easy to grip with a wrench and keep them from rotating in channels and square holes.

Also known as utility-pole nuts, these square nuts have a cupped shape that ensures a flush fit against curved surfaces and corners that bite into soft materials to resist loosening. Made from hot-dipped galvanized steel, they have a thick coating to resist corrosion in wet environments. They must be used with other hot-dipped galvanized fasteners.