An arsenal of screwdrivers for electrical installation and household needs. How to choose the right screwdrivers. A slot is a cut on the head of a screw or bolt (German: Schlitz - groove, slot), designed to transmit torque from a tool (screwdriver or socket wrench) to this product. Slots come in various shapes and sizes. In this article, we will look at the most common types of holes and the bits intended for them. Straight slot (SL) is the most popular and simplest type of slot. It is a straight groove passing through the center of the head of the fastener. The head for fasteners with a straight slot is called "slotted" or colloquially: "flat", "straight" or "minus". The working end of the screwdriver is a wedge-shaped plate. The disadvantage of this slot is that due to the lack of clear centering, the screwdriver often flies out of the groove, while the edges of the slot itself are "torn off", which is especially typical for high tightening forces. Phillips slot (PH) is a common type of hole in a fastener. The main varieties are the traditional Phillips and the more modern Pozidrive. Phillips (not to be confused with the Philips brand of equipment) is the oldest and most famous type of Phillips slot for threaded fasteners and screwdrivers or bits for them. Pozidrive (PZ) slot is an improved version of "Phillips" and is used in the production of screws and self-tapping screws for wood. In mechanical engineering and metalworking, Pozidrive is used much less often. A distinctive feature of the slot is small additional recesses, shifted by 45 degrees relative to the main axes. Pozidrive screwdrivers are not pushed out of the slot when used - a more stable grip is formed, which reduces wear on the bit and the part itself. Robertson square slot (SQ) - was first produced in 1908 by the Canadian Robertson, who introduced it into production instead of a straight slot. Hex slot (HX) - a type of slot for threaded fasteners in the shape of a regular hexagon. The angle between the sides is 120 degrees. The head of the fastener is usually cylindrical with a hexagonal recess; a screwdriver or bit with a hex head is used to work with hex slots. Torx slot (TX) - a type of slot in the shape of a six-pointed star. This slot is capable of transmitting a large torque without deforming the bit and tool. Fasteners with a TX slot are commonly used in technology: cars, bicycles, brake systems, various prefabricated metal structures, computer hard drives, ATMs, consumer electronics and fuel equipment. It should be noted that there is a difference between a TORX slot and a TORX PLUS slot: in fact, it is possible to screw a TORX PLUS screw with a TORX screwdriver, but this will lead to rapid wear of both the screwdriver and the slot itself. TORX Tamper Resistant (TXH) prevents unintentional removal of the screw. The difference from the usual TORX® is only in the hole in the center of the bit and a small pin in the center of the screw. The 3VING slot type refers to a special "three-bladed" type of slot for threaded fasteners and screwdrivers for them. Keys and screwdrivers are marked 3V or TW (Tri-Wing). The TORQ-SET type slot denotes a special "four-blade" type of slot for threaded fasteners and screwdrivers for them. Keys and screwdrivers are marked 4V or TS. The 4V slot is used only in the aerospace industry, although 4V screwdrivers are available commercially. The ONE-WAY (CL) type slot denotes a special type of slot for threaded fasteners and screwdrivers for them, intended only for tightening. When trying to unscrew the slot, the cam of the bit immediately jumps out of the groove. However, there is a head that can unscrew the CL slot. If such a "gadget" is not at hand, all that remains is to drill out the screw or, having drilled two holes in it, unscrew it with a 2P bit. A secret slot of the fork key type (2P) - with two rectangular cams, also known as "snake eyes". The slot is not designed to transmit high tightening torque, and the force is transmitted here only through two pins, which does not allow the screw to be overtightened. There is also a variation of the bit - with three pins, which, for example, is used in clutches of cold and firearms. The type of hexagonal slot with a rounded head Hexagon Balldrive (HB) - allows you to reach hard-to-reach places at an angle of up to 25 degrees. Quickly and completely inserted into the recess and reduces the problem of "breaking" the edges. Spline type slot (SP) - a slot in the form of a twelve-pointed star. The force when tightening is evenly distributed on all the rays of the star, providing the ability to transmit high tightening torque. Slot with a triangular head (TR) - a type of secret slot used by railways, fire services, and in radio electronics. My YouTube channel - / @Naitimastera VK - https://vk.com/elektrik_mag Instagram - / elektrik.magnitogorsk