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| A '''threaded rod''', also known as a '''stud''', is a relatively long rod that is [[screw thread|threaded]] on both ends; the thread may extend along the complete length of the rod.<ref>{{Citation | last = Soled | first = Julius | title = Fasteners handbook | page = 90 | publisher = Reinhold Publishing | year = 1957 | url = http://books.google.com/books?id=8OdSAAAAMAAJ&pg=PA347 | postscript =.}}</ref> They are designed to be used in [[tension (physics)|tension]].<ref>{{Citation | last = Speck | first = James A. | title = Mechanical fastening, joining, and assembly | page = 54 | publisher = CRC Press | year = 1997 | url = http://books.google.com/books?id=6KhAbKYFbH4C&pg=PA54 | isbn = 978-0-8247-9835-2 | postscript =.}}</ref> Threaded rod in [[bar stock]] form is often called '''all-thread'''.
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| == Studs ==
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| [[File:Motore Balilla PSF.jpg|thumb|[[Fiat Balilla|Balilla]] engine with cylinder head removed, showing the studs that normally hold it in place.]]
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| Studs may have a [[screw drive|drive]] slot in one end to facilitate installing the stud.
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| === Types ===
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| [[File:Судовой дизель SKL 6 DV 224, шильда, остров Тузла, август 2007 г.jpg|thumb|'Waisted' or 'undercut' studs, as engine [[cylinder head]] retainers]]
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| For studs that are not completely threaded, there are two types of studs: ''full-bodied'' studs, and ''undercut'' studs. Full-bodied studs have a shank equal to the [[major diameter]] of the thread. [[Undercut (manufacturing)|Undercut]] studs have a shank equal to the [[pitch diameter]] of the screw thread. Undercut studs are designed to better distribute axial [[stress (mechanics)|stresses]]. In a full-bodied stud the stresses are greater in the threads than in the shank.<ref>{{Citation | last = Mavrigian | first = Mike | title = High Performance Fasteners & Plumbing | page = 49 | publisher = Penguin Group | year = 2008 | url = http://books.google.com/books?id=3weCjR8nrJ0C&pg=PT56 | isbn = 978-1-55788-523-4 | postscript =.}}</ref>
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| Undercut studs (rolled thread) are also stronger because the metal is "rolled" up to the major diameter, not removed. This preserves the grain of the steel, and in some cases even enhances it. Full bodied studs (cut thread) are weaker because metal is removed to create the thread, disturbing the grain of the steel.<ref name="Green1996p1828-1830">{{Harvnb|Green|1996|pp=1828–1830}}.</ref><ref name="Green1996p1842">{{Harvnb|Green|1996|p=1842}}</ref>
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| Undercut studs are only required in applications where the stud is exposed to fatigue. Cut threads are entirely suitable for many applications, even when rolled threads might be slightly stronger. Mass-produced fasteners (standard bolts and studs) are usually rolled, but [[job production|jobbed]] parts with custom features and small lot sizes are likely to be cut.
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| == Strength ==
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| The allowable tensile force for a non-undercut threaded rod is defined by the [[American Institute of Steel Construction]] (AISC) as:<ref name="williams">{{Citation | last = Williams | first = Alan | title = Structural Steel Design | page = 151 | publisher = Kaplan AEC Engineering | year = 2001 | volume = 1 | url = http://books.google.com/books?id=vQ2ZqdhR3hUC&pg=PA151 | isbn = 978-1-58001-055-9 | postscript =.}}</ref>
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| :<math>P = \frac{0.33 F_u \pi d^2}{4}</math>
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| where ''d'' is the nominal diameter and ''F<sub>u</sub>'' is the [[ultimate tensile strength]] of the material. For undercut threaded rods the allowable tensile stress is defined as:<ref name="williams"/>
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| :<math>P = \frac{0.6 F_y \pi d_s^2}{4}</math>
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| where d<sub>s</sub> is the diameter of the shank and ''F<sub>y</sub>'' is the [[yield strength]] of the material.
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| Both equations give you units of force for the result, i.e. pounds force or newtons. The second equation state that it will deliver the allowable tensile "stress". The definition of stress is a force per unit area, i.e. [[pounds per square inch]] or [[Pascal (unit)|Pascals]] which is a [[Newton (unit)|newton]] per [[Square metre|square meter]].
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| == Class ==
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| Metric threaded rods are marked on the end with a color code to define the [[International Organization for Standardization|ISO]] strength class. The color codes are:<ref>[http://www.bomet.com/en/quality bomet.com]</ref>
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| *Unmarked — 4.6 class ([[tensile strength]] = 400 N/mm<sup>2</sup>, [[yield strength]] 240 N/mm2</sup>)
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| *Yellow — 8.8 class (800 N/mm<sup>2</sup>, 640 N/mm<sup>2</sup>)
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| *Green — A2 stainless steel (304)
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| *Red — A4 stainless steel (316)
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| *White — 10.9 class (1000 N/mm<sup>2</sup>, 900 N/mm<sup>2</sup>)
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| == References ==
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| {{Reflist}}
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| == Bibliography ==
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| {{Commons category|Studs (fastener)|Studs}}
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| * {{MachinerysHandbook25e}}
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| [[Category:Threaded fasteners]]
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| [[nl:Draadeind]]
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My name is Isabella and I am studying Philosophy and Earth Sciences at Liebnitz / Austria.
Feel free to surf to my webpage West Palm