Amachinescrew, Alsosometimesreferredtoasamachinebolt, isascrewthatistypicallydesignedtobe
fastenedtoanexisting, tappedholeonametalsurface, usuallyinconjunctionwithacorrespondingnut.
Thesetypesofscrewsarenotaslargeastheaveragescrew, usuallyranginginsizesuptothreequarters
ofaninch (19.05mm) buttheycanstillbelarger.Variationsbetweenmachinescrewsmainlyexistinoverall
boyut, shapeofthehead, slottype, uzunluk, malzeme, andcharacteristicsofthethread.
Amajorwayofcategorizingamachinescrewisbythetypeofslotinthehead, whichwilldeterminethekind
ofscrewdriverthatistodriveitintoitshole.Thetwomajorkindsofscrewdriversusedwithmachinescrews
areslottedandPhillipsheadscrewdrivers, butthereareseveralotherminortypesofscrewdriveholessuch
asTorxsix uçlu, yıldızlarla shapeddriveholesthatrequiremorespecializedscrewdrivers.Specialized
vidalı millere bağlı mandıralar
safetyreasons, sinceitismoredifficulttoacquirespecializedtypesofscrewdrivers.Adangerouselectrical
Panel, forinstance, isagoodplaceforamachinescrewwithaspecializedtypeofhole.Othermachinescrew
headscanbesimilartoahexorsquareboltthathavenoscrewdriverslotandmustbeturnedwithawrench.
Theshapeoftheheadofamachinescrewwilldeterminehowitliesonceitisfastenedtoahole.Roundand
panheadswillprotrudefromaflatsurfaceoncetheyareattached.Flat-headedscrewsaredesignedforholes
thatareboredsotheylayflushwiththesurfacewhentheyhavebeenscrewedin.Theheadofasetmachine
screwissmallerthanthediameterofthescrewthreads, sowhenitisattacheditcanbedriventhroughahole
andadjustedtoadesireddepth.
Moreofthemajordifferencesbetweenmachinescrewsareinthecharacteristicsofthethread.Thispartof
anygivenmachinescrewisoneofthemostimportant, becausethecorrespondingholesthattheyare
fastenedtowilltypicallybetappedtofitonlyonespecificsizeandtypeofscrewthread.Thesystemusedfor
characterizingdifferentthreadsusuallyfollowsISO (InternationalOrganizationforStandardization) standartlarına
whichhavebeenestablishedtokeepconsistentdesignspecificationsinmachinepartsproducedthroughout
theworld.Twoofthemajorthreadcharacteristicsareitsdiameterandpitch, thelatterbeingthedistance
betweenthreads.Thesescrewthreadscanalsobemadetobescrewedclockwise (sağ elini) ya da
(Sol el) saat yönünün tersine.
Whilethesizeofamachinescrewisusuallyrelativelysmall, therecanstillbeavastamountofvariations
betweensize, shapeandlength, mostlydeterminedbytheirintendedpurposeandhowstrongtheyneedtobe.
Pringmetal yukarıda belirtildiği gibi çoğu makine vidası üretebilir, ayrıcaÖzel madescrewscanalsobemanürün için özel üretilmiştir
ISOstandards.Machinescrewscanbemadeofanyofavarietyofmetalsorplastics.