Use of screwdrivers
Screwdrivers have been used since ancient times. And even today it is impossible to imagine any branch of industry where this simple but useful tool would not be used in common situations. It is a metal manual tool that is used for the purpose of unscrewing or screwing screws.
The main parts of the screwdriver are a metal rod with a tip and a handle, a handle that can be plastic, wooden, or metal with rubber pads. Thus, in its simplest form, a screwdriver is simply a metal rod, equipped with a tip to fit screws in their slots, and also a handle that is convenient to hold in hand that does not slip. Many workers always have at least one screwdriver in their household or a fairly serious set of them.
The handle of a typical screwdriver has a diameter of 10 to 40 mm, depending on the size of the screwdriver itself and the specifics of its scope. The larger the diameter of the handle, the greater the torque can be transferred to the screw, so the wider the screw, the wider the handle, as a rule. To work with small parts they are small screwdrivers, with small narrow handles.
Large screwdrivers are used for working with large screws, and sometimes, in addition to just a thick handle, they have a special hole on it, where an additional rod serves as a lever and allows increasing the torque.
As for the tips, in quality screwdrivers they are made of special wear-resistant alloys, for example from molybdenum steels or from chrome vanadium. This is necessary so that significant mechanical stresses do not cause the tool to become unusable too early, that is, to extend the life of the screwdriver.
Depending on the type of slot of the screw head or screw, the screwdriver is equipped with various types of tips, mainly – flathead or cross-shaped – these are the two most popular types of tips of the most common screwdrivers used at all times.
The flathead is the simplest, it is historically the first type of screwdriver, and has been used since the 16th century.
The next type of tip is cruciform, invented in 1933 by American John Thompson, who offered such screws that would fix the tip of a screwdriver in the centre of the head, and push it out when the screw is twisted. This type of tip is called today Phillips, because Henry Phillips, an enterprising engineer who founded the company Phillips Screw Company, immediately bought out Thompson’s patent, and in 1937 introduced a technology of screws and a screwdriver with cross-shaped tips at the Cadillac production, and later, during the Second World War, such screws were used to create military equipment.
If the working conditions contain electrical voltage near the work area, or the screws themselves are under dangerous voltage, then you should choose a screwdriver with a dielectric coating of the rod and with the handle protection. Such screwdrivers are marked, which reflects the level of voltage from which protection is guaranteed.