Bolt vs Screw : What is the Difference between Bolt and Screw

Bolt and screw are mechanical fasteners used to position and hold two or more components together. But they have unique applications and characteristics. Bolts are used with nuts, whereas screws make threads of their own or are used on the threaded component. But in some scenarios bolts can work as screws if used on the threaded component.

In actual practice, there is no defined difference between bolt and screws. But there are still two different categories according to their construction and applications. In this article, we will discuss the difference between bolt and screw ( Bolt vs Screw ).

Bolts and screws are mechanical fasteners used to position and hold two or more components together. This image shows the difference between bolt vs screw
Bolt vs Screw

To understand the difference between bolts and screws. Let’s first try to understand what is a bolt? and what is a screw?

What is a Bolt ?

Bolt is an externally threaded fastener used along with internally threaded components such as nuts to position and holds two or more parts. Bolts are used along with washers and nuts for high-duty applications.

Bolt is a type of externally threaded fastener, used to position and hold two or more components together and used along with washers and nuts for high duty applications.
Various Types of Bolts with Nut

During installation, the bolt remains stationary and torque is applied to the nut to hold parts together. Following are the examples of different types of bolts available in the market.

  • Hex Bolt
  • Anchor Bolt
  • Eye Bolt
  • Socket head bolt
  • U-Bolt
  • Shoulder Bolts
  • T-Head Bolt

What is a Screw?

Screw is an externally threaded fastener used to position and holds two or more components in one place. Screws do not require nuts and are assembled either in a tapped hole or create threads in pre-drilled holes during installation. They have applications for relatively low clamping force requirements.

Screw is a type of externally threaded fastener, used to position and hold two or more components at one place.
Various Types of Screw

During screw installation, torque is applied to the screw using a screwdriver. Following are the examples of various types of screws available in the market.

  • Wooden screw
  • Self-tapping plastic screws
  • Self-drilling screw
  • Machine screw etc.

What is the difference between Bolt and Screw?

Both bolts and screws are externally threaded fasteners used to position and hold mechanical components. Bolt requires nuts, whereas screws work on their own. Here is the list of differences between bolts and screws.

Bolts vs Screw

CharacteristicsBoltsScrew
ApplicationNuts are required to secure a bolt.Screws works on its own.
Torque is applied to the nut.Screwdriver apply torque on the screw.
Bolts are used with non-threaded components.Screw can be used with threaded or un-threaded components.
ConstructionUniform cross section.Can have a non-uniform cross-section.
Uniform ShankNon Uniform Shank
Clamping ForceBolts along with nuts provide high clamping force.Used for low clamping force requirements.
ReliabilityHighModerate
Load Carrying CapacityLarger size bolts are used to achieve higher load-carrying capacity. For example, bolts are used in the construction industry.Screws are not available in very large sizes. They are generally used for small load carrying applications.
ExamplesAnchor bolt, Carriage bolt, Elevator bolt, Flange bolt, Hanger bolt, Hexagon bolt/Tap bolt, Lag bolt, Machine bolt, etc.Self tapping screws, wooden screws, sheet metal screws, Machine screws, Security head screw, unidirectional screws, etc.
Applicable Standard ISO 16228:2017

To sum up, It is very difficult to differentiate between bolt and screw. Most bolts can be used as screws if used with threaded components. Click this link to know the various types of washers and their application.

We will keep updating this article on bolts vs screws. Add your comments, questions, or suggestions on the difference between bolts and screws.

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