A screwdriver is the simplest tool that should always be at hand: at home, in the country, in, because it is difficult to imagine any product that does not use threaded connections during assembly or installation. This means that replacement or repair is not possible without a screwdriver. Let's take a closer look at how to choose a screwdriver and what types of screwdrivers will be preferred when performing certain jobs.

1. Design

A screwdriver is a rod with a tip on one end, designed for a certain type of slot, and a handle on the other. Of great importance handle material and size. It can be made from plastic, wood or rubber. The shape of the handle must be chosen depending on the size of the palm: the handle that suits you will be comfortable in your hand.

Handle diameter varies from 10 to 40 mm. The choice depends on the size of the connection, the larger the threaded connection, the larger the handle should be. This way you will need to apply less force, since the handle directly transmits torque to the part. For small details choose thin screwdrivers with a small handle. Properly selected size will avoid the destruction of the handle or the disruption of the slot. Some screwdrivers have hole in the handle, which helps to apply even more force when tightening, using an additional wrench. Screwdrivers with interchangeable tips may have a cavity in the handle for storing bits.

2. Which tip is best?

It's not about the type of tip, but about the material of its execution. After all, the functionality of a screwdriver depends on the strength of the tip. With prolonged use, especially if the type of screwdriver is incorrectly selected in accordance with the slot, the tip is quickly erased, its edges may crumble and lose their original shape. Working with such a tool brings inconvenience and significantly increases the amount of time required for repairs or installation. To prevent this from happening, many manufacturers use high-strength materials for the tip, for example, molybdenum steels or chrome vanadium alloys. Many screwdrivers have magnetic tip, capable of holding small parts, which will be very convenient when working with small screws.

3. What should be the core?

Rods are square, round or hexagonal. Also they have different length, but no matter what screwdriver you need, the hardness of its rod according to GOST should be 47-52 HRC. This is a hardness index that maintains optimal strength with internal viscosity, which prevents the rod from breaking when twisting with great force. If its strength is less than 47 units, then during operation it will simply bend, and if it is more than 52 units, then it may burst. Rods, like tips, are made by conscientious manufacturers made of chrome vanadium steels. To prevent, the rod is coated with a galvanized protective layer.

4. Handle modifications

Not only convenience, but also the scope of its application depends on the shape of the screwdriver handle. Eat the usual, and probably the very first form of a screwdriver - straight, which has a wide range of applications due to the variety of sizes. But there are also improved forms of the handle, which greatly simplify the use of a screwdriver.

5. Types of screwdrivers

Technological progress does not stand still, and in order to facilitate the work of consumers in every possible way, several improved and quite popular types of screwdrivers.

6. Functional features of screwdrivers

Some screwdrivers have not quite ordinary, but very useful, additional features.

• Telescopic screwdriver. With the help of a special structure of the rod, resembling a fishing rod, you can adjust its length, and a special locking mechanism will securely fix the required length. The tips of such screwdrivers are usually magnetic, which allows you to work in difficult conditions, or to get a fallen part in a hard-to-reach place.
  
• impact screwdriver. It happens that a threaded connection can rust, get stuck or be covered with paint. Dismantling such a connection is not easy, because a lot of effort is required. For such purposes, there are impact screwdrivers that are made of high-strength steels. On the handle of such screwdrivers there is an anvil for impact or a shank - for the possibility of gripping with a key, which allows you to increase the leverage and thereby increase the moment of force. There is also a variety of impact screwdrivers that have a flat shank. When struck with a hammer, it converts the impact force into rotational force, which makes it possible to apply an even greater moment of force to the element being eliminated.
  
  
• precision screwdriver. This type of screwdriver is used when working with small parts. It has small dimensions and a slot size of up to several millimeters, which allows you to work as accurately and accurately as possible.
  
• Clock screwdriver. This is the smallest type of screwdriver. It is used for repair and replacement of watch mechanisms. The size of its tip sometimes barely reaches one millimeter. On the top of the handle there is a flat area that allows you to hold the screwdriver in one place with one finger while the shaft turns freely. This allows the smallest parts to be screwed or screwed without having to reposition the handpiece and ensures high precision.
  
• indicator screwdriver. An indispensable thing when doing. Thanks to a special mechanism built into the handle, the indicator screwdriver allows you to detect the presence of voltage on the element. The handle has a special contact to which you need to put your finger. If the part is energized, the built-in LED will light up.
  
• Dielectric screwdriver. A more serious type of screwdriver designed to work with electricity. The handle is made of a material with high insulating properties, sometimes the screwdriver shaft is also covered with such material, leaving only its tip open. This design allows you to work even on open terminals of high-voltage equipment, withstanding voltages up to 1000 V.
  
• Cordless screwdriver. A small battery is built into the handle of such a screwdriver, allowing it to work like a screwdriver. You do not need to apply any force at all, and the tightening torque will come out a little more than when twisting by hand. Such a tool can significantly speed up or assemble various products.
  
• torque screwdriver. This type of screwdriver is used in high-tech industries, aviation, mechanics, astronautics. On the handle of such screwdrivers there is a small screen that allows you to measure the tightening force, or a special scale that allows you to set the required torque and install all connections with exactly the same force.
  

7. Slot shape

Not only the screwdriver handles are varied, but also the shape of the tip, which is selected depending on the required type of slot. Consider the most common slot shapes:

8. Non-standard splines

In addition to these tips, some manufacturers have produced screwdrivers specifically designed to work with special threaded fasteners. Thus, manufacturers have protected themselves from unauthorized actions by ordinary users and provided themselves with warranty service for their products. Fasteners with non-standard slots can be found in digital technology or modern car engines.

9. Slot size

We got acquainted with the possible forms of slots, but in order for the screwdriver to serve for a long time and not be erased, it is necessary to correctly determine the required size of the tip. To determine the size of the slots, there are special standards in which each of them is assigned numbers. Screwdrivers with a flat slot have a width of 2 to 18 mm. Phillips screwdrivers PH and PZ are numbered from 0 to 4 and differ depending on the diameter of the outer thread of the fastener. For example:

Depending on the number of the screwdriver, the diameter and length of its rod depends:

• Screwdriver #0 has a shaft diameter of 4 mm with a length of less than 80 mm
• No. 1 - rod diameter 5 mm, length from 80 to 100 mm
• No. 2 - rod diameter 6 mm, length from 100 to 120 mm
• No. 3 - rod diameter 8 mm, length from 120 to 150 mm
• No. 4 - rod diameter 10 mm, length from 150 to 200 mm

10. What to look for when choosing a screwdriver?

In specialized stores, the choice of screwdrivers is so large that anyone would be confused. Sometimes sales assistants can come to your aid, but, unfortunately, they do not always recommend a really high-quality product, so you should rely only on yourself. The only thing you can do directly in the store is to carefully inspect the product, you will be able to evaluate how it will cope with its main task only after the purchase, so be careful.

Pay attention first to the handle, hold the screwdriver in your hand. it should fit comfortably in your palm and not slip. The handle itself, no matter what material it is, must be made carefully. If it is rubber, it should not have pores or excess material at the junction. Then pay attention to the rod, some manufacturers put a mark indicating what material it is made of. The presence of such a marking may imply factory quality.
The tip, as the most critical part of the screwdriver, must be very durable. Look at its color, if it is darker than the rod, this indicates additional hardening, which is a clear advantage. Even such little things can help you decide and choose the best product that will last you for many years.