Screws Buying Guide

How Do Screws Work?

In the simplest terms, screws convert torque into linear force, driving the point of the screw into the material and creating an effective mechanical hold. This linear force can be used to fasten multiple materials together and can also be used alongside a nut for added security. Screws are strong and boast increasing holding power compared to nails, yet they are also beneficial as they are typically easy to remove.

Screws have four main parts – the head, shank, thread, and point. The head is typically slotted to fit the corresponding screwdriver type. The shank connects the head and the thread, and the point is the very end of the screw which is forced into the material as force is applied. Once the point enters the material, the thread is designed to catch onto the substrate and lever the screw further into the hole.

The amount of torque a screw can generate is determined by its thread. The closer together the threads are, the more torque can be generated. This also means that more turns are needed to secure the screw.

What are the Different Types of Screw?

Many screws feature slotted heads, enabling easier access for screwdrivers. However, there is an extensive variety of different types of screws available, each best suited to varying purposes, environments, and applications. Additionally, screws can be further categorised by head type, drive type, length, diameter, and material or finish. Despite this, screws are mainly distinguished by their thread type and head shape.

Some of the most common types of screw are explained in the sections below:

How to Safely Insert and Remove Screws

Screws are relatively straightforward to use, but safety is paramount and should not be overlooked. It is also important to install screws correctly to ensure the fixing is strong and reliable.

Follow these steps to safely insert a standard screw:

• Choose a screw that is the right type and length for the application

• If you are screwing two components together, place them in position

• Mark the spot on the material where you want the screw to be installed

• If your screw needs a pilot hole, use a drill and standard bit to drill the hole

• Insert the screw into the pilot hole (if applicable) and use a screwdriver to tighten

The steps below explain how to safely remove a standard screw:

• Use a screwdriver to unscrew the fixing from the material

• Make sure to choose a screwdriver which corresponds to the screw’s head shape

• Once the screw has been loosened, you should be able to pull it out by hand

• Remember to take care as removing screws may result in loose components

How to Choose the Right Type of Screw

As there are so many different types of screws, selecting the most suitable fixing for the job can be challenging. There are several important elements to consider, and knowing the specific requirements for the intended task will also help to determine the best screw type.

Material

The material you will be screwing into will play a significant role. Some types of screws are ideally suited to specific materials, such as wood screws, while others are more general-purpose. You should also consider the material’s thickness as this will dictate the required length of screw you will need.

Size

The screw you are using needs to be the right size for the material and application. Screws should not be too long, as this could result in the screw passing all the way through the material. Screws that are too short should also be avoided as this could compromise the strength of the fastening. Lastly, the diameter of the screw should be considered, as thicker screws may split more delicate materials while thinner, smaller screws could be bent out of shape by more heavy-duty components.

Drive Type

There are hundreds of different screw drive types, but the most common drives include:

• Phillips

• Torx T and TX

• Hex

• Hex socket

• Security hex socket

• One-way

Slotted drives are the most common. They simply feature a single slot in the head of the fastener and can be driven by a standard flat-bladed screwdriver.

FAQs

What is the Best Way to Remove Rusted Screws?

Rusted and corroded screws can be commonplace, especially with older screws or those which have been left outdoors in extreme conditions. There are several ways to remove rusted screws, and the effectiveness of each will depend on the severity of the rust and the condition of the screw itself.

1. Use a hammer to strike the screw’s head, loosening the rust. You can then apply a lubricant or rust penetrant, leave it to work, then return and try to remove the screw again

2. If you have utilised the above method but the rusted screw is at risk of being stripped, you may need to re-cut notches into the screw’s head to give the screwdriver better grip. Note that proper safety guidelines should always be followed if you choose this method

3. Apply localised heat to expand the screw head, then quickly cool with water to contract, break the rust’s bond, and cause it to crack away. This may take several attempts to be successful and heat should only be used if the material surrounding the screw is non-flammable

What is the Best Way to Remove Stripped Screws?

Stripped screws occur when the screw’s head has become damaged and screwdrivers struggle to grip the head well enough to remove it from its location. As a result, they can be difficult to manage and remove.

The following methods may help remove a stripped screw:

1. The simplest method is to tap a screwdriver into the screw head, helping to improve grip

2. A specialist screw extractor is ideal for the task, as they are counter-threaded to screws and designed specifically for this purpose

3. Use an impact driver to loosen the screw enough to then remove manually or with a screwdriver. Just be careful not to accidentally tighten it instead!

4. If the screw is not countersunk, you could try to remove it by gripping the head with pliers