Coupling Nuts in Zinc Plated Steel
Nuts Used to Join Two Male Threads
Coupling nuts are threaded fasteners used to join two male threads, most commonly threaded rod. The outside of a coupling nut is typically a hex to be driven with a wrench. Coupling nuts are also used to make up long rod assemblies from shorter lengths of rods.
Coupling nuts can only connect two male threads of the same thread diameter. They can be used to tighten a rod assembly inward or to press a rod assembly outward. The industrial fastener institute describes coupling nut dimensions in standard IFI-128. Coupling nuts come in stainless steel (304 & 316), aluminum, hot-dipped galvanized steel, and zinc-plated steel finishes.
Zinc Plated Steel
Zinc is by far the most common and economical type of plating for fasteners. The zinc plating adds a protective "sacrificial" top layer against corrosion while also adding a shiny finish to the fastener. Zinc plating is ideal for indoor use, where it won't be constantly exposed to harsh elements.
The steel beneath the zinc plating of the nuts in this selection is A563 Grade A steel.
Coupling Nuts - Zinc Plated Steel - Specifications
| Nut Sizes | Flats | Length |
| 1/4"-20 | 3/8" | 7/8" |
| 1/4"-20 | 7/16" | 1-3/4" |
| 5/16"-18 | 1/2" | 1-3/4" |
| 3/8"-16 | 9/16" | 1-3/4" |
| 7/16"-14 | 9/16" | 1-3/4" |
| 1/2"-13 | 11/16" | 1-3/4" |
| 5/8"-11 | 13/16" | 2-1/8" |
| 3/4"-10 | 1" | 2-1/4" |
| 3/4"-10 | 1-1/8" | 2-1/4" |
| 7/8"-9 | 1-1/4" | 2-1/2" |
| 1"-8 | 1-3/8" | 2-3/4" |
| 1-1/8"-7 | 1-1/2" | 3" |
| 1-1/4"-7 | 1-5/8" | 3" |
| 1-1/4"-7 | 1-7/8" | 3-3/4" |
| 1-1/2"-6 | 2" | 4" |
FAQs
What is an extension nut?
An extension nut is a kind of fastener nut used to join two male threads together, such as multiple threaded rod pieces. Extension nut is a much broader name for coupling nuts, which connect two male threads of the same thread size, and reducer nuts, which connect two male threads of different sizes.
What are coupling nuts used for?
Coupling nuts are used to connect two male threads, usually threaded rods or pipes. Typically hexagonal in shape to be grabbed by a wrench, they tighten rod assemblies or extend them further outward.
What are reducer nuts used for?
Reducer nuts, or reducer coupling nuts, are used to connect two different sized male threads, usually threaded rods or pipes. Typically hexagonal in shape to be grabbed by a wrench, they tighten rod assemblies or extend them further outward, even if they have different thread sizes.
How do you join two threaded rods together?
Join threaded rods together by using coupling nuts. You can join any two externally threaded rods or bolts with coupling nuts, so long as they are of the same body diameter and pitch. If the body diameter and pitch are different between the two, use reducer coupling nuts to connect them.
What are long nuts called?
Long nuts are another name for extension nuts, otherwise known as coupling nuts or coupling reducer nuts.
