The piercing industry uses two types of threaded jewelry: externally threaded and internally threaded. While they both serve the same function, there are differences.
First, for those who are unfamiliar with the term, let us explain what threads are. The ridges on a screw are the threads. Body jewelry uses what’s commonly known as a ‘screw thread.’ The item with the threads is called the male end. Conversely, the female end is the name of the item that receives the threaded item.
When looking at body jewelry, external threads refer to a threaded shaft. The ball will screw onto the shaft. In this example, the shaft is the male end while the ball is the female. Internal threaded jewelry is the opposite. The shaft is the female end while the ball had an external threaded component that is inserted into the shaft.
Why the difference? Cost is the major factor. Internally threaded jewelry is much harder to manufacture, hence the added cost. Are there any added benefits to internally threaded jewelry? In most cases, customers who buy internally threaded jewelry are not only getting a more secure fit, but also a more comfortable piece of jewelry. Imagine having to remove a tongue barbell several times a week to clean, the threaded shaft on externally threaded jewelry will have a higher likelihood of snagging and causing discomfort when the barbell is either inserted or removed from the tongue. Where a smoother, internally threaded shaft will have a lower chance of causing such discomfort. Why would anyone buy externally threaded jewelry? Externally threaded jewelry is significantly cheaper than their internally threaded counterparts. If a piercing is completely healed and there is less of a need to remove it, then most customers will choose to go with the externally threaded jewelry.
Another thing customers need to keep in mind is that while externally threaded jewelry is cheaper than internally threaded jewelry, it should not be of cheap quality. If possible, inspect the jewelry before purchasing. One thing to look for is the number of threads on the male end. Cheaper quality jewelry will only have three rungs, or ridges while higher quality jewelry will have five. Having five rungs will ensure a tighter and more secure fit.
Finally, there are a growing number of manufacturers turning to push-in style closures. More common on labret/Monroe jewelry, push-in jewelry feature a shaft much like an internally threaded shaft but the male end is pressed into the shaft and held in place as opposed to being screwed in.