Editing Joseph Whitworth (section)

== Work ==
[[File:JFIScrewThread300.png|thumb|Graphic representation of formulas for the pitches of threads of screw bolts]]
[[File:Screw making machine, 1871.png|thumb|Screw-making machine from 1871]]

===Accuracy and standardisation ===
{{main|British Standard Whitworth}}
Whitworth popularised the [[Whitworth's three plates method|three-plates method]] for producing accurate flat surfaces (see [[Surface plate]]) during the 1830s, using [[engineer's blue]] and [[hand scraper|scraping]] techniques on three trial surfaces. Up until his introduction of the scraping technique, the same three-plate method was employed using polishing techniques, giving less accurate results. This led to an explosion of development of precision instruments using these flat-surface generation techniques as a basis for further construction of precise shapes.

His next innovation, in 1840, was a measuring technique called "end measurements" that used a precision flat plane and measuring screw, both of his own invention. The system, with a precision of one millionth of an inch (25&nbsp;[[nanometre|nm]]), was demonstrated at the [[Great Exhibition]] of 1851.

In 1841 Whitworth devised a standard for screw threads with a fixed thread angle of 55° and having a standard pitch for a given diameter. This soon became the first nationally standardised system; its adoption by the railway companies, who until then had all used different screw threads, led to its widespread acceptance. It later became a [[British Standard]], "[[British Standard Whitworth]]", abbreviated to BSW and governed by BS 84:1956.

=== Whitworth rifled musket ===
{{main|Whitworth rifle}}
Whitworth was commissioned by the [[War Department (UK)|War Department]] of the British government to design a replacement for the calibre .577-inch [[Pattern 1853 Enfield]], whose shortcomings had been revealed during the recent [[Crimean War]]. The [[Whitworth rifle]] had a smaller bore of {{convert|0.451|in|mm|3}} which was hexagonal, fired an elongated hexagonal bullet and had a faster rate of twist rifling [one turn in twenty inches] than the Enfield, and its performance during tests in 1859 was superior to the Enfield's in every way. The test was reported in ''[[The Times]]'' on 23 April as a great success. However, the new bore design was found to be prone to fouling and it was four times more expensive to manufacture than the Enfield, so it was rejected by the British government, only to be adopted by the [[French Army]]. An unspecified number of Whitworth rifles found their way to the [[Confederate States of America|Confederate]] states in the [[American Civil War]], where they were called "[[Whitworth Sharpshooters]]".  The rifles were capable of sub-[[Minute and second of arc|MOA]] groups at 500 yards.<ref name="youtube" /> It was often called the "[[sharpshooter]]" because of its accuracy, which is considered one of the earliest examples of a [[sniper rifle]].{{sfn|Atkinson|1996|p=}}{{sfn|Bradshaw|1985|p=}}{{sfn|Kilburn|1987|p=}}{{sfn|Kilburn|1990|p=}}{{sfn|Lea|1948|p=}}

[[Queen Victoria]] opened the first meeting of the [[National Rifle Association of the United Kingdom|National Rifle Association]] at [[Wimbledon, London|Wimbledon]], in 1860 by firing a Whitworth rifle from a fixed mechanical rest. The rifle scored a bull's eye at a range of {{convert|400|yd|m|sigfig=3}}.

===Whitworth rifled cannon breech-loading artillery===
{{main|12-pounder Whitworth rifle}}
[[File:CW Arty Whitworth.jpg|thumb|alt=12-pounder Whitworth breechloading rifle|[[12-pounder Whitworth rifle]]]]
Whitworth also designed a large [[rifled breech loader|rifled breech-loading]] gun with a {{convert|2.75|in|mm|2}} bore, a {{convert|12|lb|11|oz|kg|2}} projectile and a range of about {{convert|6|mi|km|0}}. The spirally-grooved projectile was patented in 1855. This was rejected by the British Army, who preferred the guns from [[William George Armstrong, 1st Baron Armstrong|Armstrong]], but was used in the American Civil War.

While trying to increase the bursting strength of his gun barrels, Whitworth patented a process called "fluid-compressed steel" for casting steel under pressure and built a new steel works near Manchester. Some of his castings were shown at the Great Exhibition in [[Paris]] {{circa|1883}}.