Dual nut or coupling nut, also known as extension nut, is used to join two male components to make a longer assembly. It is mostly used in clamps and also to join threaded bars/pipes. The outer profile is hexagonal or square for ease of tightening with tools. Normally the maximum length of the nut is three times the diameter. For dual nuts threads are normally of two different diameters having thread length half of the total length of the nut. These are used to make up long rod assemblies from shorter lengths of rods. Coupling nut dimensions are described by the Industrial Fasteners Institute in standard IFI-128. It is given a plain finish. Nuts can be machined from Hex bars or can be cold forged also. Reducing Coupling nuts have two different thread sizes.
Dual nuts can be used to tighten up a tie rod assembly both inwards and outwards.
We have in our production dual thread nut which is 16mm in length having thread of 8mm and 10mm on each side. Coupling nuts are manufactured as same ASTM specifications which are for regular hex nuts, and the dimensional specifications are as per ASME B18.2.2.
The length of engagement of the coupling nut with the bolt should be greater than the diameter e.g. for a 10mm rod the length of thread in the nut should be equal to or greater than 10 mm.
Dual Hex Coupling Nuts
Standard: DIN6330, DIN6334, DIN5587
Material: Mild Steel, Alloy Steel, Stainless steel
Surface Finish: Black, Zinc plated, Hot Dip Galvanized, Dacromet etc
Size: M8-M36;5 /16â€³-1 1/2â€³