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Wat is de skroef

Time: 2020-07-10 Comment: 41

A screw, or bolt, is a type of fastener, typically made of metal, and characterized by a helical ridge, known as a male thread (external thread) or just thread, wrapped around a cylinder. Some screw threads are designed to mate with a complementary thread, known as a female thread (internal thread), often in the form of a nut or an object that has the internal thread formed into it. Other screw threads are designed to cut a helical groove in a softer material as the screw is inserted. The most common uses of  Screws  are to hold objects together and to position objects.

In skroef sil hast altyd in kop op ien ein hawwe dy't in spesjaal foarme foarm befettet wêrtroch it kin wurde draaid, of oandreaun, mei in ark. Common ark foar oandriuwende skroeven omfetsje schroevendraaiers en wrenches. De holle is normaal grutter dan it lichem fan 'e skroef, wat hâldt dat de skroef djipper rydt as de lingte fan' e skroef en in lager oerflak te leverjen. D'r binne útsûnderingen; bygelyks, Frachtbouten have a domed head that is not designed to be driven; set screws often have a head smaller than the outer diameter of the screw; J- Bolts  have a J-shaped head which is not designed to be driven, but rather is usually sunk into concrete allowing it to be used as an anchor bolt. The cylindrical portion of the screw from the underside of the head to the tip is known as the shank; it may be fully threaded or partially threaded.[1] The distance between each thread is called the "pitch".

The majority of screws are tightened by clockwise rotation, which is termed a right-hand thread; a common mnemonic device for remembering this when working with screws or bolts is "righty-tighty, lefty-loosey." Screws with left-hand threads are used in exceptional cases. For example, when the screw will be subject to counterclockwise torque (which would work to undo a right-hand thread), a left-hand-threaded screw would be an appropriate choice. The left side pedal of a bicycle has a left-hand thread.

More generally, screw may mean any helical device, such as a clamp, a micrometer, a ship's propeller or an Archimedes' screw water pump.


Differinsje tusken bolt en skroef
In koetsbult mei fjouwerkante moer
In struktuerbout mei in hexmutter en washer.

There is no universally accepted distinction between a screw and a bolt. A simple distinction that is often true, although not always, is that a bolt passes through a substrate and takes a nut on the other side, whereas a screw takes no nut because it threads directly into the substrate. Machinery's Handbook describes the distinction as follows:

In bult is in ekstern skroefbefeiliging ûntwurpen foar ynfoegjen troch gatten yn gearstalde dielen, en is normaal bedoeld om te strak of frij te litten troch in moer te draaien. In skroef is in ekstern skroefde befêstiging dy't yn gatten kin wurde ynfoege yn gearstalde dielen, mei in foarfoarme ynterne draad parre of in eigen thread foarmje, en kin wurde strak of frijlitten troch de kop te draaien. In befestiging mei ekstern skroef dat wurdt foarkommen fan draaien by de montage en dy't allinich kin wurde strak of frijlitten troch in moer te draaien is in bult. (Foarbyld: Rûne kopbouten, Track Bolts, plooibolken.) In ekstern skroefde befestiging dy't draadfoarm hat dy't ferbining makket mei in moer dy't in rjochte tried hat fan meardere pitch-lingte is in skroef. (Foarbyld: Houten skroeven, Tappende skroeven.) [2]

Dit ûnderskie is yn oerienstimming mei ASME B18.2.1 en guon wurdboekdefinysjes foar skroef [3] [4] en bult. [5] [6] [7]

The issue of what is a screw and what is a bolt is not completely resolved with Machinery's Handbook distinction, however, because of confounding terms, the ambiguous nature of some parts of the distinction, and usage variations.[8][not in citation given] Some of these issues are discussed below:
Masjine skroeven

ASME standards specify a variety of "Machine Screws"[9] in diameters ranging up to 0.75 in (19.05 mm). These fasteners are often used with   Nuts  as well as driven into tapped holes. They might be considered a screw or a bolt based on the Machinery's Handbook distinction. In practice, they tend to be mostly available in smaller sizes and the smaller sizes are referred to as screws or less ambiguously as machine screws, although some kinds of machine screw can be referred to as stove bolts.
Hex cap skroeven

ASME standert B18.2.1-1996 spesifiseart Hex Cap Screws dy't yn grutte fariearje fan 0.25–3 inch (6.35–76.20 mm) yn diameter. Dizze fasteners binne heul gelyk Hex Bolts. They differ mostly in that they are manufactured to tighter tolerances than the corresponding bolts. Machinery's Handbook refers parenthetically to these fasteners as "Finished Hex-bouten".[10] Reasonably, these fasteners might be referred to as bolts, but based on the US government document Distinguishing Bolts from Screws, the US government might classify them as screws because of the tighter tolerance.[11] In 1991 responding to an influx of counterfeit fasteners Congress passed PL 101-592[12] "Fastener Quality Act" This resulted in the rewriting of specifications by the ASME B18 committee. B18.2.1[13] was re-written and as a result they eliminated the "Finished Hex Bolts" and renamed them the "Hex Cap Screw"-a term that had existed in common usage long before, but was now also being codified as an official name for the ASME B18 standard.
Lug bouten en holle bouten

These terms refer to fasteners that are designed to be threaded into a tapped hole that is in part of the assembly and so based on the Machinery's Handbook distinction they would be screws. Here common terms are at variance with Machinery's Handbook distinction.[14][15]
Lag skroef
Lagskroeven, ek wol lagbouten neamd
In sydbyld

Lagskroeven (ek wol lagbouten neamd, hoewol dit in ferkearde namme is) binne yn prinsipe grutte houtskroeven. Skroeven mei fjouwerkante kop en skroeven mei heksekop wurde dekt troch standerts ASME B18.2.1, en de kop is typysk in eksterne hex. In typyske efterbliuwbout kin yn diameter fariearje fan 1 mm oant 4 6.35 mm en lingten fan 1 oant 1 mm of langer, mei de grouwe triedden fan in triedfoarm (of grutter) fan houtskroef as plaatmetaalskroef.

De materialen binne normaal koalstofsubstraat mei in coating fan sinkgalvanisaasje (foar korrosjebestriding). De sinkcoating kin helder (galvanisearre), giel (galvaniseare), of doffe grize hjitgalvanisearre wêze. Lagbouten wurde brûkt om houtkaders byinoar te lizzen, om masjinefuotten nei houten flierren te efterheljen, en foar oare swiere timmerwurkapplikaasjes. It eigenskipswurd fertraging kaam fan in betiid prinsipieel gebrûk fan sokke befestigingsmiddels: it befestigjen fan efterbliuwen lykas vatstaven en oare ferlykbere ûnderdielen. [16]

These fasteners are "screws" according to the Machinery's Handbook criteria, and the obsolescent term "lag bolt" has been replaced by "lag screw" in the Handbook.[17] However, in the minds of many tradesmen, they are "bolts", simply because they are large, with hex or square heads. In the United Kingdom and Australia, lag screws are known as coach screws.
Amerikaanske regearnormen

The US government made an effort to formalize the difference between a bolt and a screw because different tariffs apply to each.[18] The document seems to have no significant effect on common usage and does not eliminate the ambiguous nature of the distinction between screws and bolts for some threaded fasteners. The document also reflects (although it probably did not originate) significant confusion of terminology usage that differs between the legal/statutory/regulatory community and the fastener industry. The legal/statutory/regulatory wording uses the terms "coarse" and "fine" to refer to the tightness of the tolerance range, referring basically to "high-quality" or "low-quality", but this is a poor choice of terms, because those terms in the fastener industry have a different meaning (referring to the steepness of the helix's lead).
Histoaryske kwestje

Alde USS- en SAE-standerts definiearden kapskroeven as befestigingsmiddels mei skonken dy't oan 'e kop waarden skroefd en bouten as befestigingsmaten mei skonken dy't foar in part net waarden skood. [19] De relaasje fan dizze regel mei it idee dat in bout per definysje in noat nimt is dúdlik (om't ferwachte waard dat de unthreaded seksje fan 'e skacht, dy't de grip hjit, troch it substraat soe passe sûnder deryn te riden). Dit is no in ferâldere ûnderskieding.
Kontroleare wurdskat tsjin natuerlike taal

The distinctions above are enforced in the controlled vocabulary of standards organizations. Nevertheless, there are sometimes differences between the controlled vocabulary and the natural language use of the words by machinists, auto mechanics and  Others . These differences reflect linguistic evolution shaped by the changing of technology over centuries. The words bolt and screw have both existed since before today's modern mix of fastener types existed, and the natural usage of those words has evolved retronymously in response to the technological change. (That is, the use of words as names for objects changes as the objects themselves change.) Non-threaded fasteners predominated until the advent of practical, inexpensive screw-cutting in the early 19th century. The basic meaning of the word screw has long involved the idea of a helical screw thread, but the Archimedes screw and the screw gimlet (like a corkscrew) preceded the fastener.

It wurd bout is ek in heul âld wurd, en it waard ieuwenlang brûkt om te ferwizen nei metalen staven dy't troch it substraat giene om oan 'e oare kant te befestigjen, faak fia net-threaded middels (klemjen, smeijen, pinnen, wigjen, ensfh. ). De ferbining fan dit sin mei it gefoel fan in doarbout as de krúsboutbout is dúdlik. Yn 'e 19e ieu waarden bouten dy't waarden fêstmakke fia skroefdraad faak skroefbouten neamd yn tsjinstelling ta bulten.

In common usage, the distinction (not rigorous) is often that screws are smaller than bolts, and that screws are generally tapered while bolts are not. For example, cylinder head bolts are called "bolts" (at least in North American usage) despite the fact that by some definitions they ought to be called "screws". Their size and their similarity to a bolt that would take a nut seem linguistically to overrule any other factors in this natural word choice proclivity.
Oare ûnderskiedingen

Bolts have been defined as headed fasteners having external threads that meet an exacting, uniform bolt thread specification (such as ISO metric screw thread M, MJ, Unified Thread Standard UN, UNR, and UNJ) such that they can accept a non-tapered nut. Screws are then defined as headed, externally threaded fasteners that do not meet the above definition of bolts.[citation needed] These definitions of screw and bolt eliminate the ambiguity of the Machinery's handbook distinction. And it is for that reason, perhaps, that some people favor them. However, they are neither compliant with common usage of the two words nor are they compliant with formal specifications.

In mooglike ûnderskieding is dat in skroef is ûntwurpen om syn eigen tried te knippen; it hat gjin ferlet fan tagong fan of bleatstelling oan 'e tsjinoerstelde kant fan it ûnderdiel dat wurdt fêstmakke. Dizze definysje fan skroef wurdt noch fersterke troch it beskôgjen fan 'e ûntjouwingen fan befestigings lykas Tek Screws foar dakbedekking, selsboarjen en self-tapping skroeven foar ferskate metalen befestigingsapplikaasjes, dakbatten skroeven om de ferbining te fersterkjen tusken de dakbatten en de dakspar, dekplaten ensfh. Oan 'e oare kant is in bout it manlike diel fan in befestigingssysteem ûntworpen om te akseptearjen troch in foarôf ynrjochte stekker (of moer) fan presys itselde triedûntwerp.


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