Coupling nuts follow the basic principles of all Nuts and Fasteners.
Thread Engagement is equal to or greater than the Bolt Diameter
With typical Finished and Heavy Hex Nuts assuring the threaded round bar is engaged to maximum strength is as simple as threading through the entire length of the nut. With Coupling Nuts the connection is often blind so it is important to gage the rod as the nut winds on. (Note: Coupling nuts can be manufactured with a site hole in the mid-point to assure full engagement.)
Fig. 1
Coupling Nuts
Standard sizes and thread engagements apply.
This 2” diameter coarse thread coupling nut measures;
3-1/8” flat to flat x 4-1/2” long.
The length provides 2-1/4” thread engagement from each side. The extra 1/4” will allow for the chamfer on the nut and the starting thread that will not fully engage.
Beyond the basic coupling nuts several variations exist that can provide solutions to unique problems.
Fig. 2
Reducer Nuts
Reducer Nuts offer varying diameters between the two sides. Stock sizes are available however they are limited to 1/8” differential from side to side, and no larger than 3/4” diameter. Greater differences and sizes can be readily produced on a made to order basis.
Fig. 3
Sleeve Nuts
The Sleeve Nut Shown is 5/8” diameter x 5” long. A standard 5/8” Coupling Nut would be 2-1/8” long. The extra length provides flexibility regarding the overall extension of the assembly. It is important to note the full length may not be usable because variations do exist between the internal and external threads. As more threads are engaged the variations multiply until the thread binds. See Below - Thread Relief.
Turnbuckle Sleeve Nuts
Threading the Sleeve Nut right hand / left hand creates a turnbuckle with the ability to tighten or extend the overall length. Similar to the extended length Coupling Nut, there is a limit to how much adjustment can be made before the threads bind as mentioned above.
Fig. 4 (below)
Thread Relief
As shown in Fig. 4 the Turnbuckle Sleeve Nut will allow as much thread as the specifications require and can go well beyond that. However, at some point the thread must be relieved as shown to cancel the possibility of binding.
Thread relief is the process of expanding the internal cavity beyond the major diameter so there is no longer contact between the threaded bolt and the sleeve. The bolt can turn freely without the risk of binding.
The Steel Supply Company specializes in providing components to
Steel Fabricators, Erectors, and the General Construction trades.
Contact us for Information or Quotes
631-212-3236