British Standard Whitworth ( BSW ) is the standard screw unit imperial-unit.
Video British Standard Whitworth
History
The Whitworth Yarn is the world's first screw thread standard in the world, designed and defined by Joseph Whitworth in 1841. Until then, the only standardization is what individuals and companies have done, with some internal corporate standards spreading slightly in their industry. Whitworth's new standard specifies the angle of the thread 55 Â ° and the threaded depth of 0.640327 p and the radius of 0.137329 p , where p is pitch. The threaded pitch increases with the diameter in the steps specified in the chart.
The Whitworth thread system was later adopted as the British Standard to become British Standard Whitworth (BSW). An example of using Whitworth threads is the Royal Navy's Crimean war ship. This is the first example of a mass-production technique applied to marine engineering, as the following quotation from the obituary of The Times 24 January 1887 to Sir Joseph Whitworth (1803-1887) points out:
The Crimean war began, and Sir Charles Napier sued the Admiralty 120 warship, each with a 60-horsepower engine, for the 1855 campaign in the Baltic. There are only ninety days to fulfill this request, and, shortly, the construction of warships does not cause any difficulties. But on the contrary with the engine, and Admiralty in despair. Suddenly, with a glimpse of the mechanical genius attached to him, the late Mr. John Penn solved the difficulty, and solved it easily. He has a pair of machines on hand with the right size. He brings them to pieces and he distributes the parts among the best machine shops in the country, telling each of them to make exactly ninety sets in everything to sample. The commands were run with an unfailing regularity, and he actually completed ninety sets of 60 horsepower machines in ninety days - an achievement that made the Great Continental Power stare in astonishment, and that may be just because of the standard of measurement and accuracy Whitworth and finished at that time were truly recognized and established throughout the country.
The original example of a gunboat type machine was raised from the wreck of SS Xantho by the Western Australian Museum. At the time of dismantling, all the threads proved to be of the Whitworth type.
With the adoption of BSW by the British railway line, many previously used their own standards for both yarn and for head profiles and bolt nuts, and improved manufacturing techniques, it became the dominant British manufacture.
In the United States, BSW was replaced when steel bolts replaced iron, but were still used for some aluminum parts in the late 1960s and 1970s when standards-based metrics replaced the Imperial ones.
American Unified Coarse was originally based on an almost identical Imperial faction. Unified thread's angle is 60 Â ° and has a flat top (rounded Whitworth peak). From 1 / 4 in up to 1 1 / 2 in, the screw pitch is the same in both systems except that the threaded pitch for 1 / 2 inside the bolt is 12 threads per inch (tpi) in BSW versus 13 tpi in UNC.
Maps British Standard Whitworth
Threaded shape
The shape of the Whitworth thread is based on a fundamental triangle with an angle of 55 Â ° at each peak and valley. The sides are on the side edge ? = 27.5 Â ° perpendicular to the axis. So if the pitch thread is p , the height of the fundamental triangle is H = p /(2 tan ? ) = 0.96049106 p . However, the top and bottom / 6 of each of these triangles are disconnected, so the actual depth of the thread (the difference between major and small diameter ) is 2 / 3 of that value, or h = p /( 3 tan ? ) = 0.64032738 p . The peak is reduced again by rounding it with arc 2ÃÆ'â € "(90 Â ° - ? ) = 180 Â ° -55 Â °? = 125 Â °. This arc has a height of e = H sin ? /6 = 0.073917569 p (leaving the depth of the straight side h -2 e = 0.49249224 p ) and the radius r = e /(1-sin ? ) = 0.13732908 p .
Standard Comparison
The English Fine Fine Standard (BSF) has the same yarn angle as BSW, but has a finer threaded pitch and smaller screw depth. It's more like a modern "mechanical" screw and used for fine machining and for steel bolts.
The standard British Standard Cycle (BSC) that replaces the Cycle Engineers' Institute (CEI) standard is used on UK bicycles and motorcycles. It uses a thread angle of 60 Â ° compared to Whitworth 55 Â ° and very fine thread pitches.
(To simplify the problem, the term hexagon will be used in this paragraph to indicate either the head bolt or nut.) Whitworth (wrench) mark refers to the diameter of the bolt rather than the distance across the hexagon flat (A/F) as in any other standard. Confusion also arises because the size of the BSF hexagon can be one size smaller than the corresponding Whitworth six hexagon. This leads to an example where the spanner (spanner) is marked 7 / 16 BSF is the same size as one marked 3 / 8 W . In both cases, the jaw width of the 0.710 spanner inside, the width across the hexagon flats, is the same. However, in World War II the size of the Whitworth hexagon was reduced to the same size as the pure BSF hexagon to store metal during the war and they never returned to the old size afterwards. So it's not uncommon today to deal with Whitworth's sixth that picks up the correct nominal wrench. The wrench in this case can be marked 7 / 16 BS to show that they have a jaw size of 0.710 And are designed for take (later) / 16 BSW or 7 / 16 Ã, BSF hexagon.
The standard screw screws of England (BA) are sometimes classified with Whitworth standard fasteners as they are often found in the same machine as the Whitworth standard. But actually this is a metric-based standard that uses an angle of 47.5 Â ° and has its own set of head sizes. BA threads have a diameter of 6 mm ( 0BA ) and are smaller, and and still very used in precision machining.
Whitworth angle 55 Â ° remains commonly used today around the world in the form of 15 standard British pipe threads defined in ISO 7, commonly used in water supply, cooling, pneumatics, and hydraulic systems. This thread is determined by the number between 1/16 and 6 originating from the nominal internal diameter (i/d) in the steel pipe inch designed this string. The marking of this pipe thread does not refer to any thread diameter.
Other threads that use the Whitworth 55A angle include Brass Thread, British Standard Conduit (BSCon), Model Engineers (ME), and British Standard Copper (BSCopper).
Current use
Commonly used British standard pipe threads (except in the US), as defined by the ISO 228 standard (formerly BS-2779), uses the standard Whitworth thread. Even in the United States, the personal computer cooling component uses the
Leica Thread-Mount used in rangefinder cameras and on many magnifying lenses is 1 17 / 32 at by Whitworth 26 per-inch, an artifact has been developed by a German company specializing in microscopes and equipped with tooling capable of handling yarns in inches and at Whitworth.
The / 32 in the Whitworth thread has been the standard Meccano thread for years and it is still the thread used by the French Mecca Company.
The most common lighting suspension lamp is 3 / 8 in and 1 / 2 in BSW. Companies originally converted into metric threads have been converted back, after complaints that smoother metric yarns increase the timing and difficulty of setting, which often occurs at the top of the stairs or scaffolding.
The materials for the garden gates have traditionally used Whitworth bolt bolts, and these are still the standards provided in the UK and Australia.
Historical abuse
The Morris and MG Engines of England from 1923 to 1955 were built using metric threads but with bolts and dim heads for Whitworth spanners and sockets. In 1919 Morris Motors took over the work of the French Hotchkiss machine which moved to Coventry during the First World War. Hotchkiss machine tools are from metric threads but metric spanners are not available in the UK at the time, so fastener is made with metric thread but Whitworth head.
In the 2011 movie Cars 2 by Disney/Pixar, an important clue to the discovery of the villain, Sir Miles Axlerod, is he uses Whitworth's bolt. Although Axlerod does not exactly resemble a real car (while many other characters are closely modeled on the original cars), it seems the closest to matching the original Range Rover Classic. In fact, the early model of Range Rovers uses parts with imperial dimensions, although the image of a criminal machine is almost identical to a 3.5-liter pleno then Rover V8 (design purchased from GM Buick).
See also
Standard other threads:
- The thread of the British Association (BA)
- English standard brass thread
- English Standard Cycle
- Standard English fine thread (BSF)
- English standard pipe thread (BSP)
- ISO screw metric thread
- Unified Thread Standard (UTS, including UNC, UNF, UNS and UNEF)
References
Bibliography
- Oberg, E., Jones, F.D., Hussain, M., McCauley, C.J., Ryffel, H.H. and Heald, R.M. (2008) Machine handbook: reference book for mechanical engineers, designers, manufacturing engineers, drawers, toolmakers and engineers <28, Ed 28, New York: Industrial Press, ISBN 978-0-8311 - 2800-5, p.Ã, 1858-1860
Source of the article : Wikipedia
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