Allen wrenches, named after the Allen manufacturing company that invented them, are “L” shaped tools. An Allen wrench is a tool that is used to provide tight connections and torque hexagon-shaped screws, or to turn these screws to open or close them. They consist of a long arm and a short arm, both of which have the same head size. These types of screws and screwdrivers have hexagonal holes in their heads, which are used to prevent the wrench from slipping off the head of the screw and to gain more control over the screw
Below is some general information about Allen wrenches:
Allen wrenches are often made of stainless steel, alloy steel, or aluminum. The head of the Allen key is hexagonal and its size corresponds to the size of the screw head.
Allen wrenches are available in various sizes, each made and used for a specific size of the corresponding screw head diameter.
Common Allen wrench sizes are millimeters and inches.
An Allen wrench is used as a hand tool, especially in various industries including construction, machine building, electronics, and automotive repair. This tool is used to tighten and torque Allen screws. There is more precise control than normal wrenches due to the hexagonal structure of their screw heads. They have higher power and efficiency in applying torque on screws. These wrenches do not slip due to the hexagonal structure of the screw head.
To use the allen wrench optimally, it is important to choose the right size for the screw head size. Regular and clean maintenance of Allen wrenches will increase their useful life.
Smaller Allen wrenches require more maintenance than larger ones. Before placing the Allen key on the screw, clean it and align it properly on all six sides.
There is a wide range of Allen wrenches for different jobs. Usually, each of the manufacturers of Allen wrenches provide a set of these wrenches in a set like a set of keys for the customer to buy.
It is better to choose the right size of the allen wrench carefully to prevent screw damage or damage to the wrench. In the following, we describe more detailed methods for choosing the right size of Allen wrench:
By choosing the right size Allen wrench, you can use a better tool to do your work and avoid screw or wrench damage. Also, it helps you to do things more accurately and efficiently.
This table is based on the size of the screw (the width of the screw strip) to the size of the corresponding Allen key:
Screw size (diameter of the screw strip) | Allen wrench size |
1.5 mm | 0.05 inch |
2 mm | 0.06 inch |
2.5 mm | 0.07 inch |
3 mm | 0.09 inch |
4 mm | 0.11 inch |
5 mm | 0.14 inch |
6 mm | 0.16 inch |
7 mm | 0.18 inch |
8 mm | 0.20 inch |
10 mm | 0.25 inch |
12 mm | 0.30 inch |
Note that depending on the country and standard, the sizes may be slightly different. This table is a general guide for choosing the right size Allen wrench, and in some cases, you can refer to the manufacturer’s instructions to be sure.
Usually, the markings on the screws are used to show the size and type of the screw. Following are examples of common markings on screws:
Example: 3, 4, 5, 6, etc
Example: M3, M4, M5, etc
The letter “M” means metric and the number after it shows the diameter of the screw tape.
In these signs, the first number indicates the diameter of the screw tape and the second number indicates the number of knots per inch.
Example: ISO 4014, ISO 4017, etc
The ISO standard uses a specific numbering for all types of screws.
Using the marks on the screws will help you to identify the size and type of the screw without exact measurements and choose the right size Allen wrench for it.
In general, you need to be careful in choosing the Allen wrench you need, and if you buy a cheap set, the small ones may not be very accurate in their measurements, meaning they fit in the size bolts. They do not work by themselves. Also, swapping sizes is never recommended, as doing so can damage the screw head and force you to replace it.