Screwdrivers


Screwdrivers have three main parts, the handle, which is gripped by the user; the shank, which is the steel portion extending from the handle; and the blade, which is the end that fits into the slot of the screw. The standard screw driver is used for most ordinary work and comes in a variety sizes. 
The blade must have sharp corners and fit the slot in the screw closely; otherwise it is likely to slip and damage the slot. It is also important that a screwdriver be held firmly against the screw to prevent it from slipping and injured the worker of the work.

The offset screwdriver makes work possible in tight corners where the straight type will not enter. It has one blade forged in line with the shank, and other blade at right angles to the shank. With such an arrangement, first one end of the screwdriver can be used then the other, changing ends after each swing, thus working the screwdriver, thus working the screw in or out of the threaded hole. 
Different types of screwdriver

Screwdriver

The Phillips type screwdriver is made with a specially shaped blade to fit Phillips-type cross-slot screws. The head of these screws have two slots that cross in the center. This check the tendency of the screwdriver to slide out of the slot onto the finished surface of the work. The screwdrivers are used to drive or remove small screws rapidly. Some screwdrivers have handles made of insulating material, and are useful when electrical work is being done. When a screwdriver with an insulated handle is not available, the handles of other screwdrivers can be insulated by wrapping them with tape. While the screwdriver shave a round shank, some heavy duty screwdriver are made with a square shank, the construction enabling the torque of the screwdriver to be increased be applying a wrench to square shank.

The tip of a screwdriver blade should be grounded so that the slides of the blade are parallel, and the blade sides should gradually taper out to the shank body. If the end of the blade is damaged, it can be made serviceable again by means of a grinding wheel. First grind the tip straight and at a right angle of the shank. After the tip is ground square, dress off from each face, a little at a time. Keep the faces parallel for a short distance or have them taper in a slight amount. Never grind the faces so that they taper in a slight amount. Never grind the faces so that they taper to a sharp edge at the tip.


Caution: Do not use a screwdriver to check an electrical circuit where the amperage is high. The electrical current may be strong enough to form an arc and melt the screwdriver blade. It is also bad practice to try to turn a screwdriver with a pair of pliers or to use it as a chisel. Do not hold work with hand while using a screwdriver. If the blade slips, it can cause a bad cut.
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