Screw is a external threaded fastener used to align and hold two or more components. Threaded screws are designed to be used either on threaded components or they create threads on their own. Screw driver or special tools are used to install screws. In this article we will discuss various type of screws.
Lot of screw types are available in the market. This guide will help you in selection of best screw for your application.
If you look at screw description. It provides complete information about the type of screw. Lets try to understand this with an example.
Screw Description : M3 X 10 Flat Slotted Head, Stainless, Machine Screw
Above screw description provides following information about the screw.
- Screw Type: Machine
- Threads Type: M3
- Screw Length: 10 mm
- Head Type: Flat Head
- Drive Type: Slotted
- Material: Stainless Steel
Types of Screw
When you look around, you can find lot of screw types. These screws are classified in following categories:
- Screw Application
- Type of Screw Head Shape
- Screw Drive Style
- Screw Thread Type
Type of Screws based on Application
Various types of screw are available based on it’s applications.
|Sheet Metal Screw||Sheet Metal pointed tip screws used to join metal parts. They require a pilot drill to create threads in metal part.|
|Machine Screw||Machine Screw require internal threads on one of the parts to be joined.|
|Set Screw||Set screws are head-less screws. These screws are used where the requirement is of headless screw.|
|Wooden Screw||Wooden screw are used to fasten wooden materials.|
|Thread Forming Screw for Plastics||These screws are used to fasten plastic parts together without using threaded fasteners.|
|Security Screw||These screws are used to ensure product can be disassembled using special tools.|
Types of Screw based on Screw Drive
Screws are available in various drive types. Selection of type of screw drive depends on it’s application. For example, uni-direction screw are used where parts are not required to disassembled.
|Phillip Drive||This is one of the most commonly used screw drive type.|
|Slot Drive||This is the oldest and commonly used screw drive type.|
|Frearson Drive||Frearson / reed / Prince screw drive is similar to a Phillips head screws. But they have the advantage of using the same screw drive bit for various screw sizes.|
|Torx Drive||Torx drive has 6 points star shape and used to transmit high torques without damaging the screw head.You can find these screws in miniature products such as watches, smartphones etc.|
|Square Drive||These screws have application in wooden industry.|
|Hex Socket / Allen Type||They have hexagonal head. They are used to transmit high torques and for applications where screw is not accessible from top|
|Pozi Drive Type||They are similar to Phillips drive type but also have an alternate cross shape.|
Screw Head Types
To sum up, Product assembly technique and its application affects the selection of type of screw. Read this article to know the difference between screw and bolt here.
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