Amachinescrew, Alsosometimesreferredtoasamachinebolt, isascrewthatistypicallydesignedtobe
fastenedtoanexisting, tappedholeonametalsurface, usuallyinconjunctionwithacorrespondingnut.
Thesetypesofscrewsarenotaslargeastheaveragescrew, usuallyranginginsizesuptothreequarters
ofaninch (19.05mm) buttheycanstillbelarger.Variationsbetweenmachinescrewsmainlyexistinoverall
размер, shapeofthehead, slottype, длина, материал, andcharacteristicsofthethread.
Amajorwayofcategorizingamachinescrewisbythetypeofslotinthehead, whichwilldeterminethekind
ofscrewdriverthatistodriveitintoitshole.Thetwomajorkindsofscrewdriversusedwithmachinescrews
areslottedandPhillipsheadscrewdrivers, butthereareseveralotherminortypesofscrewdriveholessuch
asTorxsix заостренные, звездообразные shapeddriveholesthatrequiremorespecializedscrewdrivers.Specialized
Типы винтовых отверстий могут быть важны, если требуется, чтобы
safetyreasons, sinceitismoredifficulttoacquirespecializedtypesofscrewdrivers.Adangerouselectrical
Панель, forinstance, isagoodplaceforamachinescrewwithaspecializedtypeofhole.Othermachinescrew
headscanbesimilartoahexorsquareboltthathavenoscrewdriverslotandmustbeturnedwithawrench.
Theshapeoftheheadofamachinescrewwilldeterminehowitliesonceitisfastenedtoahole.Roundand
panheadswillprotrudefromaflatsurfaceoncetheyareattached.Flat-headedscrewsaredesignedforholes
thatareboredsotheylayflushwiththesurfacewhentheyhavebeenscrewedin.Theheadofasetmachine
screwissmallerthanthediameterofthescrewthreads, sowhenitisattacheditcanbedriventhroughahole
andadjustedtoadesireddepth.
Moreofthemajordifferencesbetweenmachinescrewsareinthecharacteristicsofthethread.Thispartof
anygivenmachinescrewisoneofthemostimportant, becausethecorrespondingholesthattheyare
fastenedtowilltypicallybetappedtofitonlyonespecificsizeandtypeofscrewthread.Thesystemusedfor
characterizingdifferentthreadsusuallyfollowsISO (InternationalOrganizationforStandardization) стандарты,
whichhavebeenestablishedtokeepconsistentdesignspecificationsinmachinepartsproducedthroughout
theworld.Twoofthemajorthreadcharacteristicsareitsdiameterandpitch, thelatterbeingthedistance
betweenthreads.Thesescrewthreadscanalsobemadetobescrewedclockwise (правая рука) или
против часовой стрелки (левые).
Whilethesizeofamachinescrewisusuallyrelativelysmall, therecanstillbeavastamountofvariations
betweensize, shapeandlength, mostlydeterminedbytheirintendedpurposeandhowstrongtheyneedtobe.
Pringmetal может производить большинство видов крепежных винтов, как упомянуто выше, а также изготовленные на заказ винты, так же как и изготовленные для конкретных машин
ISOstandards.Machinescrewscanbemadeofanyofavarietyofmetalsorplastics.