The different types of screwdrivers don’t exist simply to create confusion when you send your kids out to the garage to grab a Phillips head for you. They came about to serve different needs and advancements in technology – and are still changing today.
The first flat-bladed bit for a carpenter’s brace was invented in 1744, and handheld screwdrivers began to appear shortly after; around 1800. A major advantage of the slotted screw is that it’s not particular – most of the time, just about any old standard screwdriver will do the job, and in a pinch, you can use a coin or a butter knife. Cross-head screws are simply regular slot-head screws with two crossed slots.
The Phillips head screw was developed by none other than Henry Phillips, in the 1930s, as a response to the increasing demand for automobiles. Assembly-line workers needed a fastener that could take greater torque and create a tighter hold. Not to be confused with a cross-head screw, the slots in a Phillips head screw are deeper in the center and do not go all the way to the edge, which creates a more stable hold for the driver, reducing slippage and wear. This greater stability and ability to accept more torque also allows the use of automated drivers, which led to increased assembly-line productivity and less worker fatigue.
Square and Hex
Though not nearly as common, these types of screws are more resistant to slippage than either slotted or Phillips-head. Square-slotted screws are sometimes called Roberston, because they were invented in 1908 by a Canadian named P.L. Roberston. While very stable and simple to use without creating damage, square and hex screws are very specific and will undoubtedly throw your kids for a loop, requiring you to go out to the garage yourself in search of an Allen wrench in the exact shape and size needed.
Common in Europe, this type of screw can be considered to be an improved Phillips, as it looks similar. However, it has four more contact points that allow for greater torque and help prevent the driver from slipping and damaging the screw. Pozidriv bits also decrease wear and create a larger driving surface.
Often found in electronics and increasingly being used in other applications, these screws have a 6-pointed star-shaped head, which allows for more contact between the screw head and the driver.
Tri-wing and Spanner
The tri-wing has three slots evenly spaced out on the screw head, and the spanner has two holes at the top. They are most commonly found on electronic devices where manufacturers want to discourage consumers from tampering or doing home repairs.
--By Lauren Rizzo