Phillips screw drive

However, this design is not well-suited for installation by power tools , given that a power driver often cams out of the slot; this often causes damage to the screw and surrounding material. For this reason, cruciform-slotted along with drives have replaced the slot drive in numerous applications. The tool used to drive a slot is called a common blade , flat-blade , slot-head , flat-tip [[3]]( or flat-head / flathead [[5]]( screwdriver. A hollow-ground screwdriver is less likely to cam out (leave the slot due to the torque being translated into an axial force, similar to that encountered with Phillips drive but dependent only on driver blade), so more torque can be applied without damaging the screw head. Flat-blade jeweler's screwdrivers and the tips found in 1⁄4-inch or 6.4-millimeter drive sets are generally hollow-ground. Note that it is this typical chisel shape which allows 9 screwdriver sizes to drive 24 different slotted screw sizes, with the drawbacks of not fitting as closely as a hollow-ground screwdriver would, and increasing the possibility of damaging the fastener or surrounding area. Coin slot-style screw head on a CR2032 battery housing openable using the battery itself. Coin-slot drives are so-called because of the curved bottom of the recess, which facilitates driving them with a suitable coin . They are often used on items where the user is not likely to have a screwdriver when needed, such as recessed screws that attach cameras to tripod adapters , and battery compartments in some equipment such as children's toys. [citation needed ] Hi-Torque slot drives were designed by Alcoa Fastening Systems, for situations where very high torque is needed, along with the ability to repeatedly install and remove the fastener.[[7]]( The design features curved walls, unlike the straight-walled slot drive. The Type II (Conical/Connie) design adds a conical cup that receives a centering pin on the driver, improving the alignment of the driving tool to the fastener recess. The following are screw drives based on a cruciform (cross) shape. Other names used for these types of drives are cross recessed , cross-head , cross tip , and cross-point ; sometimes "plus" (+) as against a simple slot's "minus" (−). A double slotted screw drive is not considered cruciform because the shape is not recessed, and consists only of two orthogonal simple milled slots. Some of these types are specified in ISO 4757, Cross recesses for screws . Cruciform Phillips and Pozidriv/Supadriv screws and screwdrivers look similar, and are often confused with each other; a Phillips screwdriver will often work with Pozidriv/Supadriv screws, but risks damaging the head of tight screws, while a Pozidriv/Supadriv screwdriver will damage a Phillips screw.[[8]]( The Phillips screw drive (specified as an ANSI Type I Cross Recess[[10]]( and type H in ISO documentation) was created by John P. Thompson, who, after failing to interest manufacturers, sold his design to businessman Henry F. Phillips .[[11]]( [[12]]( Phillips is credited with forming a company (Phillips Screw Company") ), improving the design, and promoting the adoption of his product.[[11]]( The original 1932 patent[[13]]( expired in 1966, but the Phillips Screw Company continued to develop improved designs.[[11]]( The American Screw Company") of Providence, Rhode Island , was responsible for devising a means of efficiently manufacturing the screw, and successfully patented and licensed their method; other screw makers of the 1930s dismissed the Phillips concept because it called for a relatively complex recessed socket shape in the head of the screw, as distinct from the simple milled slot of a slotted screw. The Phillips screw design was developed as a direct solution to several problems with slotted screws: high cam-out potential; need for precise alignment to avoid slippage and damage to driver, fastener, and adjacent surfaces; and difficulty of driving with powered tools. The design is o