Screwdrivers are very useful mechanical hand tools required for inserting and removing screws. They are one of the most widely used mechanical devices with a multitude of variations to cater to different types of screws. Each screwdriver consists of three parts; Handle, Shaft or shank, and Drive tip or bit. The head of screws normally has a cavity and protrusion to fit the screwdriver tip. A torque is then applied to remove or drive the screw. In this article, we will learn about the various types of screwdrivers and their uses.
Applications of Screwdrivers
Screwdrivers are one of the most essential and sought-after tools for any tool kit. For loosening and tightening different types of fasteners, there is no alternative to screwdrivers. They are used in various applications like
- Opening mobile phones
- Electronics and electrical equipment
- Opening computers
- Woodworking and carpentry
- Mechanical and industrial production
- Metalwork and fastening wood to metal
- Flammable environments, etc
Screwdrivers are available in many different sizes. They are usually sized as standard large, medium, and small. Certain screwdrivers are also sized to use in tight or confined spaces. The screwdriver tip width and the length of both the blade and the overall tool are generally measured in millimeters (mm).
Again, depending on the manufacturer, the screwdriver sizing can vary. For example, Phillips screwdriver provides four standard screwdriver sizes ranging from #0 to #4, where #0 represents the smallest screwdriver. On the other hand, certain screwdrivers are sized based on the Torx size. The size is specified by the letter T followed by a number. For instance, T10 screwdrivers. This screwdriver sizing method ranges from miniature screwdrivers to T45 and beyond. The same sizing system is applied to screws as well which in turn helps in deciding the screwdriver size for a particular sized screw.
Types of Screwdrivers
In general, screwdriver types are determined based on the drive tip shape to fit specific types of screws. Again, certain types of screwdrivers are applications specific to particular industries. Using the right type of screwdriver to the screw saves effort and time, both. The following section provides a guide to the most common types of screwdrivers.
Cross-head Screwdrivers or Phillips Screwdrivers
Cross-head screwdrivers or Phillips screwdrivers are designed to fit screws with Phillips heads having a cross-shaped recess. They are available in sizes from size zero to size four. Phillips screwdrivers are invented to cope with higher torsion. Their angled tips allow fitting deeper into the screw head which reduces the chances of the driver sliding out.
Torx or Star Screwdriver
Torx screwdrivers are popular by various names like star head screwdrivers, pointed screwdrivers, or six-point screwdrivers. The trademark name for a six-point star-shaped intrusion in the screw head is Torx. This type of screwdriver is suitable for transferring higher torques without the tool slipping. Torx screwdrivers are available in a range of sizes. It uses a numbering system that starts with the letter T followed by a number, for example; T8, T15, T10, T25, etc. With the increase in the number, the size of the tooltip increases. Torx screwdriver is widely used in the Automotive industries.
Insulated screwdrivers provide added safety in potentially hazardous situations and because of this, they are also known as safety screwdrivers. These types of screwdrivers are widely popular among electricians. The insulation is usually made from non-conductive rubber materials.
A torque screwdriver is quite similar to a torque wrench and is used to provide a specified controlled torque. They work using a torque-limiting clutch that has a limit on the applied force beyond a certain threshold.
Flathead Screwdriver is also known as the slot-headed screwdriver. This type of screwdriver is quite common and has multi-purpose applications. With their flattened tip, flathead screws provide a linear straight movement.
Mainly used for specialized devices like consoles, mobile phones, and cameras; Tri-wing Screwdrivers possess quite small tips to enable use with smaller screws and components.
An upgraded version of Philips Screwdrivers, Pozidriv screwdrivers are designed to reduce cam-out where a screwdriver slips out of the screw head on the application of more torque.
As the name hints, they are hexagon screwdrivers used to work with hex screws. Allen keys or wrenches are typical examples of Hex Screwdrivers.
To reduce the cam-out issue of the slotted screws and speed up the fastening process, the square-headed screwdriver that fits screws with a square-shaped recess was developed.
Electric Screwdrivers and Impact Drivers
Electric Screwdrivers are compact power tools required for various tasks like assembling furniture or screwing into softwood or other similar materials. Whereas, Impact drivers, are essentially a more heavy-duty screwdriver type that is used for jobs requiring sudden force to drive into or remove from harder, denser materials.
Precision screwdrivers are suitably used for very small devices where extremely small screws are used. Typical examples are mobile phones, watches, etc.
Magnetic Screwdrivers have an inherent magnetic force that allows the screws to be attached at the tip. They find major applications in the electronics industry where screws are small and have a high potential to be dropped easily.
With a built-in mechanism that allows the application of force only in one direction while allowing free movement in the other direction, Ratcheting Screwdrivers function similarly to ratchet spanners.