Jun 16, 2016

Coupling nuts, also called extension nuts, are used to join two threaded rods or pipes, including threaded rods or pipes of different sizes. Usually constructed in a hex shape for wrench hold, the most common uses for coupling nuts include tightening rod assemblies or to pushing a completed rod assembly outward.

  • The Industrial Fasteners Institute describes coupling nut dimensions in standard IFI-128
  • If you need to join two different sized threads, Copper State carries reduced coupling nuts in low carbon steel.
  • Eye coupling nuts attach to vertical beams to suspend your thread rod vertically. Select from a 3/8-16 offset eye or a standard eye in 1/4"-20 or 3/8"-16. 
  • If the threads you're joining are of equal diameter and pitch, select from coupling nuts in zinc, yellow zinc, and low carbon steel in a full compliment of sizes. 
  • Coupling nuts are threaded right-hand. If you need a right-to-left coupler, sleeve nuts are an excellent alternative. 
  • The nut diameter is the bolt size, so a 1/4" 20 nut will thread a 1/4" 20 bolt. The thread count is also the same. 

Your project may require that the threaded parts entering each end of the coupling nut engage half of the coupling nut's thickness. In this case, drilling a hole in one side of the middle of the nut will provide a visual inspection window through which you can confirm that the rod ends are meeting in the middle.

Copper State Bolt and Nut is committed to being the finest in manufacturing and distribution. We're proud to support each of our customers with years of knowledge and expertise. Please contact us with questions about specific projects, differentiating between the fasteners in this category, or for suggestions for purchases. We're here to help.