JIS B 1012: A Standard for Cross Recesses for Screws
JIS B 1012: A Standard for Cross Recesses for Screws
JIS B 1012 is a Japanese Industrial Standard (JIS) that specifies the shape, dimensions and measurement methods of cross recesses for screws. Cross recesses are the slots on the head of a screw that allow a screwdriver to fit and turn the screw. JIS B 1012 defines three types of cross recesses: H type, Z type and S type. Each type has different characteristics and applications depending on the size and purpose of the screw.
The H type cross recess is the most common type and is suitable for screws with a nominal diameter of M1.6 or more. It has a symmetrical shape with four wings and an angle of 7 degrees or 5 degrees 45 minutes between the wings and the base. The H type cross recess conforms to ISO 4757-1983 (Cross recesses for screws).
Jis B 1012 Pdf 17
The Z type cross recess is designed for screws with a nominal diameter of M2 or less, or M3 or less with a small head. It has an asymmetrical shape with two long wings and two short wings, and an angle of 7 degrees 45 minutes or 6 degrees 20 minutes between the wings and the base. The Z type cross recess also has an angle of 4 degrees 23 minutes or 3 degrees between the long wings and the short wings.
The S type cross recess is used for screws with a nominal diameter of M2 or less, or M3 or less with a small head. It has a symmetrical shape with four wings and an angle of 4 degrees between the wings and the base. The S type cross recess is similar to the Phillips type cross recess, but has narrower and more vertical slots.
JIS B 1012 also provides the methods for measuring the wing length, gauge depth and engagement of the cross recesses using gauges that match the shape and dimensions of each type. The standard was first published in 1974 and revised in 1985. It was reaffirmed in 2021.JIS B 1012 is widely used in Japanese made equipment, such as cameras and motorbikes. It is also compatible with ISO 4757-1983, which is an international standard for cross recesses for screws. JIS B 1012 ensures that the screws can be driven by a screwdriver with a blunt point and less tendency to cam out (slip out of the slot due to excessive torque). JIS B 1012 also provides the general requirements for standardized bolts, screws, studs and nuts that use cross recesses.
JIS B 1012 is one of the many standards for cross recesses for screws that exist in the world. Some other examples are Phillips, Pozidriv, Torx, Robertson and Tri-wing. Each standard has its own advantages and disadvantages, depending on the application and environment. Some factors that affect the choice of cross recesses are torque transmission, wear resistance, ease of installation and removal, security and availability.
JIS B 1012 is a useful standard for anyone who works with screws and screwdrivers. It helps to ensure a proper fit and function of the fasteners and tools. It also helps to prevent damage to the screw head and surrounding material. JIS B 1012 can be obtained from the Japanese Standards Association (JSA) or from online sources. 0efd9a6b88
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