Coupling nuts, or extension nuts, are threaded fasteners used to join two male threads, typically threaded rods or bolts. The main types of coupling nuts are as follows:
Hex Coupling Nuts
• Have a uniform, hexagonal shape and are used for general-purpose applications.
• Come in different thread sizes to accommodate various connections.
• Readily available in the market with a Unified National Coarse thread pitch.
• Low strength and typically ungraded.
• Available in plain, hot-dip galvanized, and zinc-plated finishes.
Heavy Hex Coupling Nuts
Made with a thicker wall and wider dimension across the flats for increased strength.
• Used in applications requiring higher load-bearing capacity.
• Often not readily available in the marketplace.
• Can be manufactured to both low-strength and high-strength specifications.
Reducing Coupling Nuts
• Designed to connect two rods or bolts of different diameters.
• One side has a larger internal thread diameter than the other.
Round Coupling Nuts
• Feature a cylindrical shape
• Can be manufactured with a wrench flat for ease of installation
• Typically used where a smooth, aesthetic appearance is desired, when hex bar is not readily available, or when expedited lead times are desired.
Stop Type Coupler
• Designed to limit the depth to which the threaded rods or bolts can be inserted.
• Features an internal “stop” or partition in the middle of the coupler, which prevents the threaded elements from going past a certain point.
• Frequently used in construction and structural applications, such as rebar splicing, where it’s crucial to control the insertion depth for strength and safety requirements.
Each type of coupling nut serves a specific purpose depending on the application requirements, including strength, aesthetics, or environmental considerations.
Benefits of Using Coupling Nuts:
o Durability: Provides a strong and secure connection for high-load applications.
o Adjustability: Can fine-tune tension or alignment by tightening or loosening.
o Ease of Use: Simple design allows for quick and efficient connections without specialized tools.
o Customizability: Available in various materials (e.g., stainless steel, zinc-plated steel) and thread sizes to meet different requirements.