It’s hard to even begin to comprehend how much standardized fasteners and hand tools have changed the modern world. Let’s dig a bit deeper and I’ll share with you the things you need to know when it comes to understanding screwdrivers, screws, and the various screwdriver bits you can use to help you get jobs done.
Screwdrivers have been around since the 15th century but didn’t really become quite so commonplace until the industrial revolution. With the invention of automated industrial processes the creation of reliable & uniform screws become possible.
Until the automation of screw manufacturing each screw had to be handmade and that made each screw unique and for a specific application. Once screws could reliably be manufactured to exacting specifications then the screwdriver would become an integral part of every tool chest.
I’ll start with ones you’re most likely to need in everyday use both on the job or around the home. To keep things clear, I’ll show you both the screwdrivers and the screws in order to help you understand more.
Common Screwdrivers and Screw Types
- Also called a cross-recessed bit, it is one of the two standard screwdriver heads and is found in many places commonly. I use these screws in personal projects as well, as there are many lengths you can buy and of many different types of metal, with steel being the most common.
- This is the standard flathead or “slotted” screwdriver. Whenever possible I replace flathead (slotted) screws with Phillips head screws because slotted screws are difficult to turn very tightly in many cases – and at times they can barely work at all. This is because there are far fewer points of contact inside the slot in relation to how the screwdriver fits and if your screwdriver isn’t fairly close to the size of the slot in the screw, it won’t want to stay in place while you’re trying to turn it. Phillips is much better. I honestly don’t even know why these are used; they’re so lousy it makes no sense to me in this day and age!
- Also called a hex screwdriver type these screwdrivers were originally invented in 1910 by the Allen Manufacturing Company. You definitely will run into these when working on things such as machinery, cars/trucks/heavy equipment (and especially their engines), and a variety of other places where high-torque fasteners are required. In my opinion a definite must-have for your toolbox!
- These are good for when you have to attach something in a tight space and are also pretty good for very tight fastening situations. It can be turned by an outside hex screwdriver (commonly called a nut drive also), socket and ratchet, or a wrench.
- Designed to replace Phillips heads in industrial applications the Torx or star heads provide a better grip and resist cam-out (popping out) when tightening. The are used commonly in many areas from automobiles to consumer products. I have had to use these screwdrivers many times and keep several in my toolbox already. They have sizes listed such as “T15”, “T30”, and so on.
Other Less Common Types
- This is an improved version of the Phillips head but the head is not tapered to a point. Instead the head is flat sided all the way down and offers improved grip and reduced chance of stripping the screw head. (See photo at the top)
- This is another modified Phillips head used for mostly marine applications and allows for higher torque. Not so common, and you’ll need a closely matched screwdrive to use it.
- The Robertson is a popular screw head in Canada and can be seen in other areas of use at times. I’ve run across this one from time to time, often used on furniture. The square head bit fits snugly into the screw head and it can hold it there even when the driver is being used with one hand or when placed on the end of a cordless screwdriver.
- These fit socket wrenches as well as purpose made screwdriver bits. Their advantage is that there is no recess to trap water and also they handle extra torque well when tightening. The good thing is that often you can use an Allen wrench in them and won’t need to purchase a special screwdriver.
Security Hex Socket
- Similar to a standard hex socket but designed to be tamper proof and require a special bit or screwdriver to turn.
- A Torx driver specifically designed for anti-tampering screws – basically a Torx with a center divot preventing you from using a regular Torx screwdriver.
- Uses a triangular shaped driver and is primarily used in kid’s toys and a few other less common areas. The TP3 is basically the same except for having curved inner surfaces in the scew head.
- The screw head is slotted with three wings and was originally used in the aircraft industry. Presently it is used mostly in electronics like phones and gaming consoles. I once had to purchase one to open a Nintenod Gameboy Advance system and it is used on other game consoles as well.
- This is a cross shaped drive used in applications where it needs to be torque sensitive.
- Also called a snake-eyes, pig nose, drilled head or twin hole. This driver is used in applications where tampering is discouraged. I’ve run across this one in places like public restrooms or where panels are located and the screws are used to prevent vandalism or access to areas where unauthorized people could place others in harm.
- There are two types of clutch heads (A and G types) and resemble a bow tie.
Tamper Resistant One-Way
- One way screws are designed specifically so that they can only be turned one way. Once they are in they are not coming back out. I’ve most often seen these used in bathroom stall mounts on the wall, for some reason.
- The double square forms an eight-pointed star as if two squares where superimposed on one another.
- Similar to the double square but forms a 12 pointed star.
- These driver heads have 6 teeth that resist camming out. It is used in high torque application for the automotive industry.
- This driver has 12 equally spaced tips and is used in high torque applications like tamper resistant lug nuts.
- The heads are made from two hex shapes offset from each other. They can accept a standard hex bit but at higher torque there is a chance for the heads to round off.
- These are made with four to six plines. Bristol screw drives are used in softer metals as the force of the turn is at right angles to the screw head and resists stripping the head.
- Five lobes protrude from the center of the driver. It’s used by Apple products to resist tampering.
There’s a lot of different fasteners out there, but basically only a relative few that you’ll commonly need to be concerned with. Screws have specific applications depending on the type of engineering they are a part of. Most types are made to either deal with high torque, resist over tightening of screws, or made specifically to resist being removed or being tampered with.
Many tool sets will have just the basic types of screwdrivers for the most common applications while a few others will have a wider range of types specifically for electronics.
I recommend that unless you’re only needing a specific type of screwdriver for now, I recommend you pick up the following in order to be prepared for most common types of fastener removal or installation:
- A Phillips head screwdriver set and 2-3 flat head screwdrivers or one flat head screwdriver set
- A miniature screw set (contains both phillips and flat head)
- Standard and metric allen wrench sets of the type shown above
- Torx screwdrivers or Torx bits to be used in a nut driver with bit holder shaft
Have any questions, ideas, or still confused? Let me know here!