What Is the Difference Between Screws and Bolts?

With the rapid development of modern science and technology in our country, people’s daily life is almost inseparable from all kinds of fasteners. When consumers buy screws or bolts or even nuts, they often confuse the fasteners to be purchased because of a lack of understanding of screws, bolts, and nuts. Today, YIJIN Hardware will tell you the difference between screws and bolts.

What Is the Difference Between Screws and Bolts?

In fact, in the fastener industry, there is no strict distinction between screws and bolts. But the small ones are mostly called screws. Such as self-tapping screws, set screws, wood screws, etc.; Larger screws are called bolts, such as hexagonal bolts, expansion bolts, carriage bolts, joint bolts, and square head bolts, etc. What’s the difference between screws and bolts?

bolts with washer manufactured by YIJIN Hardware

  1. A bolt is a type of fastener composed of a head and a screw. It needs a nut to be used in conjunction with it. Only a light hole is required on the connector. It is generally used when the thickness of the two parts is similar at the connection. As for the shape of the head, the head of the general bolt is flat, and the head of the screw has various forms according to the application.
  2. Screws are also a type of fasteners consisting of a head and a screw. They can be divided into three categories according to their uses: machine screws, set screws, and special-purpose screws. The connection of screws requires tapping on the connected parts to form threaded holes, which are generally used for the connection between thinner and thicker parts. Screws and bolts are functionally connected and fasteners.


Structurally, bolts have various styles of “heads”; The stud has no “head”; the screw also has a variety of “heads”, but the “head” structure is different. The “head” of the screw generally has fastening grooves, hexagon sockets, etc., which can be tightened by hand. The screw will be knurled on the “head”. This makes the size of the screw smaller. Application: bolts are generally used in pairs with nuts for through holes, which can be easily replaced after damage; studs are also generally used in conjunction with nuts, mostly for blind holes, and the connected parts need to be disassembled frequently; screws are also mostly used for blind holes when the connector is removed.

bolts with washers manufactured by YIJIN Hardware In addition, the tightening tools are also different. Bolts generally use wrench-type tools, while screws generally use screwdriver-type tools; There are differences in the fastening methods. The bolts are generally used in conjunction with nuts or screwed into the processed bolt holes. In addition to these two methods, there are also self-tapping screws, which are directly screwed into the workpiece with relatively soft material without machining the bolt holes. For example, what we call wood screws is this kind of screw; The appearance is different. The head of the bolt generally adapts to the shape of the tool, such as hexagon bolts and hexagon socket head bolts, whose heads are exposed outside the workpiece. , and the head of the screw is generally flush with the surface of the workpiece, those screws that are not self-tapping should also machine a slope on the surface of the workpiece, just so that the screw head is flush with the surface of the workpiece.

high-strength carriage bolt manufactured by YIJIN Hardware


In our life, we will see all kinds of bolts and screws, as well as the cooperation of nuts. When we use these standard parts, we must distinguish whether these fasteners are national standards or non-national standards, and these fasteners. The specifications are used so that we can clearly distinguish the size and purpose of bolts and screws when using these fasteners so that we can better understand and use these bolts and screws in the future.

Expand Knowledge

The Role of Gasket

On the one hand, the gasket plays the role of dispersing the load to prevent the bolt from falling into the connected parts when tightening; on the other hand, the gasket can play a role in preventing loosening.

Especially when the connection surface is not very smooth, it is easy to loosen without a gasket. In addition, if the connection surface is crushed, it cannot be installed again later. The gasket should be hard enough. Especially for high-strength bolts (grade 8 and above), hardened spacers must be used.

Thank you for reading, have any questions about fasteners, or CNC machining parts, send your request and get the most favorable quote.


Leave a Reply

Get a quote