A Complete Screw Buying Guide

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A Complete Screw Buying Guide

The humble screw, which most people are familiar with, is one of the most important technological advancements in human history. With the screw, people were able to build stronger, and more durable structures and vehicles, making it possible for further advancements in engineering and technology. Today, screws are commonplace objects, but they still are an important technology, as without screws, modern construction techniques would not likely be possible.

Screws are widely available in hardware stores, as well as online at websites like eBay, but those wanting to buy screws should be aware of a few things. First, there are many kinds of screws, each one used for a different purpose or with different materials. Secondly, different screws have different heads, which may determine how they react in different situations. Finally, it is important to understand thread types and screw lengths. Understanding all of these factors can make it possible for anyone to find the right screws for any project.

Types of Screws

Screws are all designed with the same function, which is to hold two items in place. Screws are one of the most basic machines in existence, but have a lot of power. All screws use the same design, which is a thin cylinder with threads winding up from the tip. Some screws have a pointed tip, although this is not always the case.

Drywall Screws

Drywall screws were designed to replace the nails that were commonly used to hang drywall. Even though that is their ostensible purpose, drywall screws have become very popular for a number of other applications as well. Part of this is due to the fact that drywall screws are sturdy, with a point on the end that makes them ideal for many different tasks. There is also the fact that drywall screws began replacing nails at the same time that electric screwdrivers were introduced. Drywall screws are almost a perfect fit for use with an electric screwdriver, which makes them easy to use and to fasten in place.

Deck Screws

Deck screws are designed to be very similar to drywall screws, and are also very compatible with electric screwdrivers. The main distinguishing feature of a deck screw is a pointed end and threads that only reach three quarters of the way to the top. This design feature allows deck screws to be driven flush with the surface of the wood.The main difference between deck screws and drywall screws is that deck screws are waterproof and designed to avoid rust. This is a problem that drywall screws do not have to deal with, as they are usually placed in dry environments. Generally, deck screws can be used on a variety of projects, from building box gardens to making a wooden toy box.

Wood Screws

Wood screws are different from deck screws, although they are both designed to be used with wood. Wood screws generally come in a variety of different shapes and sizes. The threads on wood screws are generally quite coarse, which means that it is less likely for the screw to come loose or be removed, even with significant force.

Sheet Metal Screws

Sheet metal screws are usually the same thickness as a wood screw, but the threads go all the way up to the top of the screw. Like wood screws, sheet metal screws are designed with coarse threads that hold firmly to a substance. However, as a general rule, the fact that the threads cover the entire screw means that sheet metal screws grip better than wood screws, and for this reason, can be quite popular for wood projects, as well as for fastening sheet metal. Like wood screws, sheet metal screws come in several different sizes, and with differently shaped heads to better fit individual projects.

Lag Screws

Lag screws are usually very long screws that have a bolt shaped head. This means that they must be turned using a socket wrench rather than a screwdriver. Lag screws are generally used for attaching something flexible, like a gate to a fence or a floor to studs in a building. Lag screws, due to their size and length, are generally very stable.

Masonry Screws

Masonry screws are different than most other kinds of screws in that they are meant to be inserted into masonry or other very tough surfaces. It is necessary to use a masonry drill to make a hole before the screw can be inserted. Generally, masonry screws are not used for anything other than attaching something to brick or concrete.

High-Low Screws

High-low screws are known by their threads. These screws actually have two sets of threads; these threads are of alternating heights. The purpose of high-low screws is to attach firmly to softer materials with a lower density, like plastic or light wood.

Self-Tapping Screws

Self-tapping screws are unique in that they are designed with threads that actually taps the hole left by the screw. In other words, the screw advances as it is turned. The result of this design is that a hole does not need to be drilled before the screw can be put into place. Self-tapping screws are meant to be used for softer materials such as plastic.

Other Screws

There are many other different kinds of screws, all made for different purposes. Many of them do not have special names, and are instead distinguished by length or by thickness. For those looking to buy screws on eBay that are not special purpose screws, it is helpful to know what size to look for. This can make the buying process much easier, and even help to eliminate the possibility of buying the wrong size.

Screw Heads

Screws come with very different heads. While most screws can be used with either a standard or Phillips head screwdriver, some are meant to be used with allen wrenches or other specific tools, like a socket wrench. Heads are also designed to perform different functions. Some heads are meant to fit flush against a surface, while others are meant to be raised slightly in order to remove them if necessary.

Screw Head Type



Standard size and height


Rounded top


Rounded top; wide diameter


Flat top; tapered underside


Slightly rounded top: deep profile

There are variations within each general type of screw head. There are also unique heads, such as for hexagon screws, that do not fit the typical standard styles. Different screw heads can be used with different fastening tools, depending on the use of the screw and the manufacturer.

Buying Screws on eBay

Screws are among the many tools that are available on eBay. In many cases, buyers may discover a much wider selection of screws than they may have initially anticipated, even in the case of rare or hard to find screws. The best way to find the appropriate screws for a specific job is to first evaluate the job and then discover what kind of screws are needed. This means noting the correct length and thickness for the task and using these measurements to find screws. Screws can be found by using the search bar available on any eBay page. A simple search term, like "screws" may provide many results, but to save time, it is helpful to include the type of screw desired and any other considerations, such as length.

Be Thorough

Screws are such small items, and are so dependent on size, that it is easy to make mistakes when buying on eBay. For this reason, it is helpful to read the product description to make sure that screws purchased are indeed the right size and shape. It is always possible to ask questions of the sellers and have them verify any details that may not be included in the product description.


Screws have made it possible for human beings to move from thatch-roofed cottages to massive skyscrapers. Today, screws, one of the simplest of machines, are extremely important and millions of them are used every year in construction and hobbies. Screws come in a variety of different shapes, and are made from unique materials that are designed to withstand the elements and variations in climate. Popular screws include the drywall screw and the wood screw, both of which are meant to be used with an electric screwdriver, or an electric drill that has a screwdriver bit attached.

One of the most important features found in modern screws are threads that are designed to grip distinct materials. Wood screws and sheet metal screws have purposefully rough and coarse threads that grip very tightly. Other screws have threads that are meant to work on softer materials like plastic. One of the most important factors of any screw design is the head. A screw's head design might allow it to stay flush and smooth against a surface, or it may stand out in order to be removed more easily. Some screws have rounded heads that reduces the possibility of injury should someone accidentally run into them. Understanding the different options available for screws can make it possible for anyone to find what they need for any project.

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