A Guide to Different Screw Heads and Their Purposes

A Guide to Different Screw Heads and Their Purposes

22 Feb 2023
Fasteners knowledge
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An example of the different types of screw heads.

The humble screw is often overlooked when it comes to acknowledging its importance in building the modern world. Since its invention in 300 B.C., the screw has become commonplace in every aspect of our civilization. When it comes to building machines and gadgets, the screw is an irreplaceable entity whose universal existence keeps our world together, literally! When it comes to popularity, even the iPhone is second to the screw, considering it contains over 100 screws no bigger than 1mm. 

Screws come with different head types, and in different sizes and materials. Today, we’ll explore the purpose of each one of them. 

How Screws are Made & the Materials Used

Hundreds of millions of screws are made each day in factories all over the world, and they’re all manufactured in a similar fashion. The two most common ways of making screws are:

Reciprocating die - Using two flat dies where one is stationary and the other moves back and forth in the horizontal plane, the screw material in the form of a thick wire is fed into the dies and shaped when the dies come together. It’s an extremely efficient way of manufacturing screws and can typically produce up to 260 screws per minute. 

Centerless cylindrical die - The thread is created by rolling two or three round dies around the screw. This is also the most precise method of making screws with accurate threads. They tend to produce high-quality and high-strength screws because there is less fatigue in the metal. 

Materials

Socket-type screw heads are used extensively in motorsports applications.

Screws are made from various materials for different purposes, and some are even made from plastic, but these tend to have limited fastening capabilities due to their weaker material. The most common materials for screws are:

Steel - The most widely used in the world, steel screws are so prolific simply because they are the cheapest material on this list. The downside is that steel screws are prone to iron oxidation (rust) which can cause weakness if used in moist environments. 

Copper - Although they cost more than steel, copper screws possess better corrosion resistance and are the preferred material for screws exposed to the elements. They’re durable enough to provide good fastening ability in the long term. 

Stainless steel - Screws made from this material can withstand long term usage in harsh environments and, depending on the stainless steel grade, can withstand exposure to moist environments. Due to their shiny finish, they are visually more appealing, which makes them suitable for use on exterior surfaces. However, due to their low carbon content, they are not as strong as steel. 

Titanium - Typically chosen for its strength and lightness, titanium screws are used when extreme weight savings far outweigh cost considerations. They’re often used extensively in competition-level racing machines where every gram of weight matters. Titanium screws are also popular in medical applications because of their corrosion resistance. 

Types of Screw Heads

There are many different types of screw heads on the market, each serving a different purpose. The type of screw head matters because it will also determine its accessibility and the tools used to fasten it. 

Flat head - The grandfather to all other types of screw heads, the flat head screw is the most popular in the world. It’s easy to make, relatively cheap, and gets the job done. A flat head is easily identified by a single line that divides its head evenly. The flat head is recommended to be used with hand tools only as the shallow slot is prone to slipping. Powered drivers will tend to slip and damage the surrounding areas. Flat heads are commonly used in low-torque applications like carpentry. 

Phillips head - Second only to the flat head, the Phillips's head was invented as an improvement over the flat head. Compared to the flat head’s two-point contact, the Phillips's head allows more torque to be applied through its four-point contact. However, when too much torque is applied, burring can occur, causing a stripped screw. 

Socket head - Unlike most other screws, socket head type screws use a hexagonal drive that is tightened and loosened with an Allen key wrench. This allows socket head screws to be used in high torque applications as they are able to generate much higher clamping force than other screws. This means fewer screws need to be used on the workpiece. An added advantage is that because of the accessibility Allen keys offer, socket-type screws can be used in tight spaces. 

Nejireo.com produces a wide variety of high-quality Japanese screw fasteners available in various materials, designed for numerous industrial applications. With no MOQ and over 100,000 items in stock, we are able to provide a fastener to suit your applications. We also have a variety of sizes ranging from M1 - M100. Contact us today to find out more.

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