Types of screwdriver bits
Contenido
Existen muchos tipos de destornilladores según el tipo de punta, o lo que es lo mismo, según el tornillo con el que se adaptan perfectamente para trabajar.
Las puntas de destornilladores más habituales son:.
Grooved
The tool used to drive a slotted head screw is called standard, common blade, flat blade, slot head, straight blade, flat, flat point,[7] or "flathead".[8] This last usage can be confusing, because the term flathead also describes a screw with a flat top, designed to be installed in a countersunk hole. Additionally, the term implies that a screwdriver has a "head"; It's not like that. Such a flat head screw can have a slotted, cross, square or combination head. Before the development of newer bit types, the flat blade was called "common blade", because it was the most common. Depending on the application, the name of this screwdriver may differ. Within the automotive/heavy electrical industries, it is known as a "flathead screwdriver";[9] within the avionics and mining industries, it is known as a "standard screwdriver".[10] Although there are many names; the original 1908 device was known as a "panhead screw."
Among slotted screwdrivers, variations in the blade or tip end involve the profile of the blade when viewed from the front (from the side of the tool). The most common type is sometimes called keystone, where the profile of the blade is slightly widened before tapering at the end, providing additional rigidity in the working surface and making it able to withstand more torque. To maximize access in applications with restricted space, the sides of the "cabinet" variant screwdriver blade are straight and parallel, reaching the end of the blade at a right angle. This design is also frequently used in jeweler's screwdrivers.
Many textbooks and vocational schools instruct mechanics to grind the tip of the blade, which, due to the taper, increases its thickness and consequently allows for more precise engagement with the screw slot. This approach creates a set of graduated slotted screwdrivers that fit a particular screw to achieve a firmer fit and reduce deformation of the screw head. However, many better quality screwdriver blades already have "induction tempered" (heat-treated surface), and polishing the tips after manufacturing compromises their durability. Therefore, it is best to select a tip made to fit precisely to begin with and avoid weakening the factory heat treatment.
Phillips
Phillips screwdrivers come in several standard sizes, ranging from tiny "jeweler's" to those used for assembling a car frame, or , respectively. This size number is usually stamped on the shank (shaft) or handle for identification. Each bit size fits a variety of screw sizes, more or less well. Each Phillips screwdriver size also has a related shank diameter. The driver has a 57° tip and tapered and blunt (rounded) flutes. The smaller y bits come to a blunt tip, but the larger y bits have no point, but rather a nearly square tip, making each size incompatible with the other.
The design is often criticized for its tendency to exit at lower torque levels than other "cross head" designs, an effect caused by the tapered profile of the flutes which makes them easier to insert into the screw than other similar styles. There has long been a popular belief that this was actually a "deliberate" design feature. Evidence for this specific narrative is lacking and the feature is not mentioned in the original patents.[11] However, a later refinement of the original design described in the patent [12][13][14] describes this feature.
Robertson
The Robertson screwdriver, also known as square,[15] or Scrulox[16] has a square-shaped "Square (geometry)") socket on the head of the screw and a square boss on the tool. Both the tool and the socket have a tapered shape, which makes inserting the tool easier and also tends to help keep the screw on the tip of the tool without the user needing to hold it there. (The cone's first rationale was to make screw manufacturing practical by using cold-formed heads,[17] but its other advantages helped popularize the unit.) Robertson screws are common in Canada, although they have been used elsewhere,[18] and have become much more common in other countries in recent decades. Robertson screwdrivers are easy to use one-handed, because the tapered socket tends to retain the screw, even if it is shakes.[18] They also allow the use of angled screwdrivers and trim head screws. Robertson socket head screws are self-centering, reduce cam, stop a power tool when tightened, and can be removed if painted or old and rusty.[18] In industry, they speed production and reduce product damage. One of their first major industrial uses was the production of the Ford Motor Company's Model A and Model T. reliable and saved considerable production time, but it was unable to obtain a license for them in the United States, so it limited their use to its Canadian division only. Robertson head screwdrivers are available in a standard range of tip sizes, from to .
Reed and Prince
Reed and Prince, also called Frearson is another historic cross head screw configuration. The cross on the screw head is sharper and less rounded than a Phillips, and the bit has 45° wings and a sharper, more pointed end. Additionally, the Phillips screw slot is not as deep as the Reed and Prince slot.[19][20][21] In theory, R&P screws of different sizes will fit any size R&P bit.[22].
Pozidriv
Pozidriv and the related Supadriv are widely used in Europe and most of the Far East.[23] While Pozidriv screws have cross heads like Phillips and are sometimes thought to be the same, the Pozidriv design allows for higher torque application than Phillips. It is often claimed that they can apply more torque than any of the other commonly used star screwdriver systems, due to a complex fluting (coupling) configuration.
Japanese Industrial Standard (JIS)
Japanese Industrial Standard (JIS) Phillips screwdrivers remain another standard, often incorrectly called "Japanese Phillips." Compatible screw heads are usually identified by a single recessed point or "X" on one side of the cross slot. This is a screw standard throughout the Asian market and Japanese imports. The driver has a 57° tip with a flat tip.[24].
Other types
Many modern electrical appliances, if they contain screws, use screws with heads that are not the typical slotted or Phillips styles. Torx is one such pattern that has become more widespread. It is a knurled tip with a corresponding recess in the head of the screw. The main cause of this trend is manufacturing efficiency: the tips of Torx screwdrivers do not slide out of the fastener as easily as a Phillips or slotted screwdriver would. (Slotted screwdrivers rarely do. They are used in mass-produced devices, since the screwdriver is not inherently centered in the fastener).
Atypical fasteners are common in consumer devices for their ability to make disassembly more difficult, which is considered a benefit to manufacturers, but considered a disadvantage by users than if more common head types were used. In microwave ovens, these screws prevent casual access to the high-power kilovolt electrical components, which are very dangerous.
However, Torx and other drivers are widely available to the consumer due to their increasing use in industry. Some other styles fit a three-point star recess and a five-lobe slot with rounded edges instead of the square edges of the Torx. This is called Pentalobe.
Specialized patterns of security screws are also used, such as the Line Head (LH) style from OSG System Products"), Japan, as used on many Nintendo consoles, although drivers for the more common security heads are, again, readily available. Another type of security head has smooth curved surfaces instead of the slotted edges that would allow the screw to be loosened; it is found on privacy screens in public bathrooms and cannot be removed with conventional screwdrivers.