Screwdrivers date back to the early 15th century, when they were invented to tighten the newly-invented screws used in metal suits of armor and engines for war.
However, not much has changed in the technology of screws and their drivers, and the only real developments during the past several hundred years was an increase in the variety of drives, improvements of metals used in their manufacture, and the design of more efficient screwdriver handles.
Today, much of the success of modern technology and industry depends on the humble screw and its corresponding driver. So, if you are planning a DIY project, or are shopping for new screwdrivers, read on! Because in this article, we will tell you everything you need to know about screwdrivers.
Uses and applications
Below is a table that lists the most common types of screws head and screwdrivers, and their common uses.
Type of Drive
Most commonly used in the manufacture of furniture, electronics, jewellery and carpentry.
Previously used in almost all applications, the slotted drive is becoming increasingly rare in mass-produced goods.
Typically used on a wide range of products for the European market. Pozi-drive is not common in the USA.
Typically used in the manufacture of furniture due to the efficiency of the drive.
Typically used in electronics and automotive industries.
Typically used in the manufacture of furniture.
Tri – Wing
Some electronics manufacturers use this drive to prevent the users from tampering with their products.
Typically used with electronics, restroom doors, and elevators.
Graphical guide about Screw Head and Screwdrivers Head.
Types of Screwdrivers
There are many types of screwdrivers available in the market,But most popular head are Phillips, slotted and Pozi.
Here is detail review of each type.
1.Phillips Head Screwdriver:
When viewed from the front, the tip of the screwdriver looks like a cross, but in high-quality screwdrivers, the actual tip of the tool will be rounded. Tools with sharp, almost needle-like tips will not fit screws made in the west. So, do not buy them unless you are working with screws that match their narrower profile.
Phillips screwdriver sizes Guide
High-quality Phillips screws are always marked with a number engraved on the head, and this number denotes the size of the drive required.
For general DIY purposes, the #2 Phillips drive is the most commonly used one. Although it is available in sizes ranging from 1 to 4, there are larger ones for industrial applications as well.
This is the oldest style of drive, and it is merely a slot cut across the full width of the screw. However, slotted screws are becoming increasingly rare, because of the difficulty in tightening them to high torque values without damaging the head.
Slotted-head screws require a tool with a flat blade, and there are several sizes available to fit screws of different sizes. However, the angle of the tapered tip when viewed from the side is of critical importance, since it determines how well the tip will grip the sides of the slot. High-quality tools have tips that are very near and parallel to the tip to prevent it from slipping out of the slot under high torque values.
Below is a table that indicates the width of the flat blade in relation to various sized slotted screws. It is very important to use the correct screwdriver with each size screw to avoid damaging the slot drive.
The Pozi-drive was developed by the Phillips screw company in collaboration with the American screw company. The purpose of collaboration was to eliminate the tendency of the normal Phillips screwdrivers to cam out of the drive because of the angles between the screwdriver and the screw.
In this drive, the angles in the drive are reduced, and the corresponding reduction of the angle on the screwdriver tip ensures improved contact between the drive and the tip. This greatly reduces the chances of the driver to slip out of the drive. It means that higher torque values can be applied to these screws without damaging the heads. The drive is also enhanced by four shallow radial lines between the main recesses to provide additional contact points.
Pozi-drives are not as common in America as they are in Europe and elsewhere. They usually come in sizes ranging from 1 to 3.
4.Robertson Drive (Square Recess):
Also known as the Robertson drive, the drive in these screws is a recessed square. Since there are no angles involved, it is almost impossible for a driver to slip out of the recess, which means that very high torque values can be applied. In fact, it is more likely that the screw will snap off before the square-shaped driver will slip out of the drive.
This drive is configured like a six-pointed star, but with the points rounded off. There are no angles involved, and the large contact area between the screw and its driver provides excellent contact. It also means that these screws can be tightened to very high torque values.
However , the drives in these screws are relatively shallow, so some care must be taken. Make sure there is no dirt, or other solid material in the drive that can reduce the effective contact area between the drive and the driver. Torx drives are available both in internal and external drives, and corresponding drivers are available in sizes that range from T1 to T100.
Hex drives have six straight sides, hence the name, hexagon drive. However, most hex drive fasteners are bolts, rather than screws. Nevertheless, there are screwdrivers available to drive them. The most common use of hex fasteners is in the assembly of furniture, but using a T-handle allen wrench is often the better choice when working with these screws because it allows application of higher torque values than is possible with a narrow-handled screwdriver.
Other, Less Common Screw Drives
Some manufacturers of consumer goods have developed special screw drives that make it almost impossible to disassemble their products. This is mainly to prevent tampering with electronic devices that carry heavy electrical current. Below are two examples of tamper-proof screws:
This one is similar to the Phillips drive. But instead of four recesses that form a cross, this drive has only three, which makes it almost impossible to remove such a screw without the correct driver. While Tri-Wing drivers are available, they are expensive, and not easy to find. Nonetheless, Tri-Wing screws can be tightened to very high torque values, and they come in sizes that range from 1 to 3.
This type of screw drive is not in common use outside of the electronics industry. It consists of two eyes or recesses at the edge of the screw head. The corresponding driver has two prongs, much like a pitch-fork that allow the recesses to turn the screw. The fact that no other screwdriver or tool can be used to turn these screws makes them tamper-proof. They are available in sizes from 4 to 12.
Screwdrivers Buying Guide
The quality of a screwdriver is arguably more closely related to its price than that of any other class of tools. Therefore, it is very important NOT to buy cheap, unknown brands. The most common problem with substandard screwdrivers is that the tips, regardless of the type, do not fit the drive of the screws properly.
Phillips screws are a good example. Some manufacturers in Asia and the Far East make the cross-shaped drive in their screws narrower and deeper than similar screws made in the west. And while the screwdrivers that are made to fit screws of eastern manufacture work perfectly, the sharper profile of these screwdrivers mean that they do NOT work on screws made in the west, because they do not match the profile of the screw drive.
There are other examples like the tips of cheap screwdrivers are either too soft or too brittle, which means that they can easily break under load. As a result, the screw gets damaged to a point that it becomes almost impossible to extract it even by using high-quality tools.
So, when you are shopping for screwdrivers, always look for reputable brands, and take along a sample of the screws that you are going to be working with. Test the tip of the screwdriver against the drive to ensure a proper fit, and do not purchase tools that do not match the drive in the screw perfectly.