Understanding Screwdriver Types

By: HowStuffWorks.com Contributors  | 
A man and a woman building kitchen cabinets. 

Having the right tools is the difference between a quick and easy job, and a real headache. The wrong screwdriver rarely works, but choosing the right one requires a modest understanding of various screwdriver types. Fortunately, you've come to the right place.

Screwdrivers are a fundamental component of every tool box, and most households have at least a couple of them floating around. Full screwdriver sets are widely available and reasonably affordable. And, assuming you've selected the right screwdriver for the screw head, even the cheapest screwdriver will get the job done.


They aren't all created equally though. The more you pay, the more functions your screwdriver can have. There are a wide variety of options, all featuring a wide array of function combinations. Screwdrivers are generally classified into the following categories:

  • Manual: Manual screwdrivers are composed of a plastic handle that extends into a cylindrical rod that ends with a screwdriver tip.
  • Electric screwdrivers: These are powered by electricity from an outlet or wall, and perform the same function as their manual cousins, though with a lot less work.
  • Ratcheting screwdrivers: Ratcheting screwdrivers house a mechanism that makes tightening and loosening screws much easier than manual screwdrivers.

The screwdriver functions mentioned above don't mean much if you don't pair them with the appropriate screwdriver heads. So with that in mind, it's time to take a closer look at those.


Phillips Screwdrivers

The Phillips screwdriver, with its distinctive cross-shaped tip, is a staple in both professional and household toolkits. Invented in the 1930s by Henry F. Phillips, it was designed to provide a secure fit with a Phillips screw.

Phillips screwdrivers come in various sizes, from #000 to #4, to match different screw head sizes. Using the correct size is crucial to avoid stripping the screw head. They are widely used for tasks ranging from furniture assembly to electronic repairs due to their availability and ease of use.


A notable drawback of Phillips screws is their tendency to slip out under excessive torque, a feature initially intended to prevent over-tightening. Despite this, their unique design and functionality have made them a staple of modern toolboxes.

The Hex Key Screwdriver

The hex key screwdriver, commonly known as an Allen key, is a compact tool used for driving bolts and screws with hexagonal sockets. Its distinctive L-shaped metal design allows for secure engagement and minimizes the risk of stripping the screw head. Invented by William G. Allen, the hex key is essential for assembling furniture, bicycles, and electronic devices, especially in tight or confined spaces [source: Schoenfeld].

Available in various sizes, it's important to use the appropriate size for each task to prevent damage to the screw head. The hex key's simplicity and solid construction enable it to withstand significant torque, making it suitable for high-force applications.


While its shape allows access to restricted areas, the L-shape can be cumbersome in certain situations, and precise alignment with the screw head is necessary, which can be time-consuming. Despite these limitations, the hex key screwdriver's effectiveness and durability make it a valuable tool in both DIY and professional settings.

The Flathead Screwdriver

Flathead screwdrivers, also known as slotted screwdrivers, are a classic tool with a flat-bladed tip designed to fit into the single slot of a flathead screw. Its simplicity and wide availability make it a staple in various settings, from household repairs to electrical work.

Flathead screwdrivers are available in different sizes to match various screw heads. While the design allows for versatility and can be used for prying or scraping, it has limitations, such as a tendency to slip out of the screw slot and a lower torque capability compared to Phillips or hex screwdrivers.


Robertson Screwdrivers

The Robertson screwdriver, known for its square-shaped tip, is tailored for driving screws with a square recess. Invented by P.L. Robertson, this screwdriver stands out for its high torque application and reduced risk of slippage, thanks to its snug fit with the screw head [source: Robertson Screw].

Available in various sizes, often color-coded, the Robertson screwdriver is particularly favored in woodworking and construction due to its self-centering design, which is ideal for one-handed operation and working in tight spaces.


Despite its advantages, such as minimized cam-out and enhanced torque, the Robertson screwdriver is more popular in certain regions like Canada and may not be as readily available elsewhere. Proper sizing is crucial to avoid damaging the screw head.

The Pozidriv Screwdriver

The Pozidriv screwdriver, designed for Pozidriv screws, features a cross-shaped tip with extra lines between the arms, offering increased torque and reduced slip-out risk. Its tip, flatter and with additional ribs compared to a Phillips, ensures a tighter fit and greater control [source: ACCU].

These screwdrivers come in various sizes, labeled "PZ," and must be matched with the appropriate screw size to prevent damage. While Pozidriv screwdrivers are excellent for high-torque applications in industries like construction and automotive, they are not interchangeable with Phillips tools.


Overall, the Pozidriv screwdriver is a specialized tool ideal for precise, high-torque tasks, though it's less universally recognized than Phillips or flathead screwdrivers.

Torx Screwdrivers

The Torx screwdriver, featuring a six-pointed star-shaped tip, is tailored for Torx screws and excels in high torque applications [source: Haus of Tools]. Its unique design minimizes cam-out, enhancing the durability of both the screw and the screwdriver.

Torx screwdrivers come in various sizes, denoted by "T" followed by a number (e.g., T15, T25). Using the correct size is crucial to prevent damage. While they excel in industries like automotive and electronics due to their precision and resistance to slipping, their specialized nature means they're less versatile than common Phillips or flathead screwdrivers.


In essence, the Torx screwdriver is a specialized tool, ideal for tasks requiring precision and high torque, but with limited application outside of specific fields.

The Right Tool For The Job

The world of screwdrivers is diverse and specialized, with each type catering to specific needs and applications. From the versatile flathead and Phillips to the precision-oriented Pozidriv, Torx, and the secure-fitting Robertson, each screwdriver plays a crucial role in various industries and DIY projects.

While Phillips and flathead screwdrivers offer versatility and ease of use, making them staples in any toolkit, the Robertson, Pozidriv, and Torx screwdrivers provide specialized solutions for tasks requiring more precision or higher torque. Understanding the unique characteristics and appropriate applications of each type is essential for both professionals and hobbyists to ensure efficient, safe, and effective use.


This overview underscores the importance of choosing the right tool for the job, not only to achieve the best results but also to extend the life of both the tools and the fasteners. Whether in a professional workshop or a home garage, whether you're using tiny screws or slotted screws, the right screwdriver can make all the difference in the success of a project.