subject: Sheet Metal Screws Explained In Detail [print this page] Introduction to screws Introduction to screws
A screw is a hardware component that is used for fastening or positioning two or more objects. The fastening qualities of a screw come from the fact that it has a threaded shank. The threaded shaft gives the screw retention in metal, plastic, wood, or other materials. While some screws have a fully-threaded body, there are other types that have a partly threaded body. In a fully-threaded screw, the threads (also referred to as a helical ridge), stretches from the tip of the screw till the underside of its head. For instance, sheet metal screws are fully threaded to give them an unmatched grip. However, in a partially-threaded screw, the threads are machine only on a particular part of the screw.
Types of screws
Screws can be classified into two categories based on their shank. These two categories are:
1. Screws with a tapered shank: The most common example of such screws would be sheet metal screws. In such screws, the shank could be either slightly tapered or very pointed and sharp. These screws do not necessarily require a pre-tapped hole. They are self-tapping owing to their tapered shank.
2. Screws with a non-tapered shank: Such screws are primarily used in conjunction with another fastener such as a nut. They need a pre-tapped hole into which to be driven.
Screws for fastening sheet metal
The construction, automotive and metal fabrication industry relies on sheet metal screws to firmly hold together or secure the position of two or more sheets of metal. Such a screw can be recognized based on certain distinct characteristics. Here are a few:
1. It has a series of sharp threads along its entire shaft. There are a few exceptions wherein the threading stops short of the underside of the screw head.
2. These sharp threads allow the screw the create threads into the substrate as it is driven in.
3. These screws are also referred to as thread cutting screws because they form mating threads while being driven into a substrate.
4. In some cases, such screws might be notched at their head. The notch helps in removing chips when the thread cutting process is carried out.
5. Thread cutting screws are used with other materials such as wood and plastic.
A cautious approach during purchase
Thus, it is evident that these screws are rather vital to several fastening operations. They demonstrate good retention, making them a worthwhile investment. It is important to note at this point that sheet metal screws should always be procured from a reputable distributor. The hardware components market is brimming with substandard goods, and only a distributor of quality products can help you in completing your task at hand.
