A threaded rod is akin to a bolt minus the head with the thread running the almost the entire length of the rod. It is also known as a ‘stud’. It is also in bar stock form and called all-thread rod. Threaded rods are made to be used in joints with more tension.
Depending on where you are going to use it, you need to buy the right threaded rod. They are available in different lengths, thickness and types.
There are some that are not threaded the entire length and there are two types in these- full bodied threaded rod and undercut threaded rod. The comparative information below will give you a fair idea of the differences between them:
In the full bodied threaded rods, the thickness of the shaft or shank is equal to the major or outer (bigger) diameter of the thread. In the undercut ones, the thickness of the shaft is equal to the pitch or inner (smaller) diameter of the thread. The undercut threaded rods or studs are so designed because the axial stress is more evenly distributed. However, in the full bodied threaded rods, the threads take the greater stress than the shank.
The undercut threaded rods are stronger because it is made by rolling the metal up to the major diameter and not by removing or cutting the metal. In this process, the grain of the steel is preserved and even enhanced at times. On the other hand, full bodied threaded rods are relatively weaker because the metal is removed or cut from the shaft to make the threads, thereby disturbing the steel grains on the rod.
The undercut threaded rod are majorly used in applications where there is more fatigue generated. Although rolled threads may be the stronger of the two, cut threads are the ones that may be more suitable in a variety of applications.