A ‘Coupling Nut’, also known as ‘Long Nut’ is a long threaded ‘Fastener-Nut’ used for joining two male threaded fasteners, most commonly a ‘Stud’ which is also a relatively long rod. The coupling fastener is a hex shaped nut that can be tightened & loosened with a handheld wrench.
These nuts are manufactured using a cold forged and hot forged technique depending on its applications. The coating used for these nuts is Electro-Zinc Plating, hot dip galvanizing; phosphate coating, silver plating, chrome plating and many other coatings are also done.
A Coupling Nuts length varies from 3mm to 20mm clearly giving a firm grip to the threaded rods. So these nuts are also called as ‘Extension Nuts.’
The Several types of the ‘Coupling Nuts’ are
1. Left-handed Nuts: These are used to make long joints from a shorter length of the studs using coupling nuts.
2. Sight Hole Nuts: A hole on the side of a nut allows visual verification that the threads are engaged.
3. Reducing Long Nuts: This kind of nut has a bigger end and a smaller end at the fastener that allows joining of two different size thread bolts.
A ‘Coupling Nut’ is internal finely gripped threads that hold the threaded rods or studs significantly overcoming the compressive stress in the two mating threads and a tensile strength in the coupling nut without loosening over the time period. Also, they are available in the various metal forms such as Brass, Stainless steel & Aluminium.
The Features of Coupling Nut are
1. Greatly customized with higher dimensional accuracy.
2. Supreme strength with a perfect grip.
3. Black-oxide finish protects from corrosion.
4. Engagement of the studs can be visualized from a small hole.
5. Higher tensile strength and longer durability.
The Applications Of Coupling Nut are
1. Engineering Applications.
2. Automotive assemblies.
3. Oil fields.
5. Nuclear Projects and Instrumentation.