CE Approved Fasteners As Per EN-15048 Part-1 and 2, Hex Head Screws / Bolts, Cup Square Mushroom Head Screws, Crash Barrier Fasteners, Eye Bolts, Other Forged Items, Square Head Bolts & BS 7419 Square Bolts, Carriage Bolts, Road Crash Barrier Fasteners, Nuts, Threaded Bars / U-Bolts / L-Bolts / Eye-Bolts, Washers / Sheet Metal Components.

2. Fasteners are used in manufactured
products for several basic purposes:
Theysimplify manufacture.
Theysimplify repairs.
Theyprovide safety.

3. When selecting a fastener for a
particular use, consider these factors:
Strength:Willit holdtheloadsandpressures?
Security:Willit remain attached?
Cost:Realistic?
Installation: Appropriatefor situation?
Skill: Isspecializedtraining needed?
Equipment:Isspecializedequipmentneededandavailable?
Appearance:If thefastenershows,whichkindlooks best?

4. Nails – Most common method of fastening
one wooden member to another.
Simplest&quickest.
Maynotresultinthe
strongestof joints.
Manydifferentsizes
andvariousshapes
ofheads,points&
shanks.
Eachtypedesigned
foraparticular
purpose.
Drivenailsatangles
slantingtowardor
awayfromeach other
togetbest holding
power.
Nails are
designated
by “penny” size,
originally a term
which related to price
per hundred but now
signifies length. The symbol
for penny is the lowercase letter
“d”. Nail diameter increases with
length. Nails are now sold by the pound.

5. Screws – A large and important family of fasteners.
Machinescrews Setscrews
Themostcommontypesofscrewsare:
Woodscrews Sheet-metalscrews
“Mechanical devices for fastening things together. Essentially a
cylindrical or conical piece of metal threaded evenly around its
outside surface with an advancing spiral ridge and commonly
having a slotted head: it penetrates only by being turned, as with a
screwdriver.”
UseCategories

6. Wood Screws
Servemuchthesamepurposeasanail,but:
Providegreaterholdingpowerthananail.
Screwscanbeeasilyremovedand replaced.
Screwsareneaterinappearanceandoffermoredecorative
possibilities.
In additiontofasteningpiecesofwoodtogether–the
mostcommonuseofwoodscrewswouldbetoanchor
objects(hardware)toawoodsurface.

7. Sheet-Metal Screws
Alsocalled“TappingScrews”or“Self-ThreadingScrews”.
Usedtofastenlightpiecesofmetaltogetherortoattachcovers,
panelsandotherlight parts.
Thesescrewshavesharpthreadsthatcancuttheirowngrooves
intometal.
Theycomewith“coarse”or“fine”threadsandareusuallycase
hardenedtocutthreadsandwithstandhardtwistingforces.
Distinguishablefromwoodscrewsinthattheyarethreadedall
thewayfromthepointtothe head.

8. Machine Screws
Usedfortheassemblyofmetalpartsandusuallyaredriven
into“threaded”holesratherthandrawn tightwithnuts.
Likeall screws,therearemanyheaddesignstochoosefrom.
Machinescrewthreadsarealsodesignatedbythenumberof
threadsperinch,justlikebolt threads:
A6-32machinescrewhasa#6bodydiameterand32threadsper
inchof length.
Mostmachinescrews arefullythreadedtothehead.

9. Set Screws
Frequentlyusedtoholdaknob,collar,pulleyorgearto
arotating shaft.
Thereareavarietyof“head”or“point”styles,eachbest
suitedforits job.
Generallymadeofhigh-strengthmaterialandareheat
treated.
Notanespeciallystrongtypeoffastening–dependon
frictionand“shear”toholdparts together.

10. Once you have decided to use screws, in
addition to the use category, you must
consider four things before ordering.
Typeof head
Materialmadeof
The length
Thediameter

11. The “type of head” should include both the
“shape” and the “style”.
Pan Head
Hex Head
Flanged Hex Head Truss Head
Screw Head “Shapes”Screw Head “Styles”

12. The most common “material screws are
made of” is steel.
If thefastenerisexposedto the
“weather”–steelalonedoesnot offer
muchprotectionagainstthe harmful
effectsofcorrosion.
Coatingsoffermore protection.
SteelBlued
ZincCoated
Chromium
Galvanized
Nickel
SilverPlate
GoldPlate
MarineApplications
mayrequire different
metalsand/ormaterials.
StainlessSteel
Aluminum
Copper
Brass
Bronze
SyntheticMaterials
(PlasticorNylon)

13. The “length” of screws commonly range
from ¼ inch to 4 inches. Shorter or longer
lengths are generally special order items.
(Metric lengths are also available)

14. Screw diameters can be expressed by the
“gauge” number or by the fraction of an
inch. (Metric diameters are expressed in mm)

15. American Screw Gauge
Sizesaredesignatedbylengthin inches
(millimeters).
Diameterslessthan¼inch(6mm)usegauge number.
Diametersgreaterthan¼inchusefractionsofan inch.
Woodscrewsareanexceptiontothisruleinthatthey
generally gouptoa#20gauge(21/64”).

16. Bolts, Cap Screws, Nuts & Washers
Nomenclatureofbolt-typefastenerstendstobeconfusing.
Boltsareusuallyusedinplainholesdrilled throughthepartsbeing
fastened.
Boltsaregenerally held in placewith amatingnut.
Whenthenutforanyboltisturneddownonwood,alwaysuseaflat
washerunderthe nut.
Capscrewsarenormally usedin threadedholes, without anut.

17. Machine Bolts/Cap Screws
Machineboltshavesquareorhexagonalheads.
Installed witha wrench.
Usuallyusedif thepartstobejoinedaremadeofmetal.
Capscrewsgenerally lookjust like amachinebolt.
Slightlydifferent application.
Screwedinto threadedholes ratherthanbeingusedwith anut.

18. Round-HeadBolts
Commonlyusedtofastenwoodparts.
Mosthaveasquareneckunderthehead.
Alsousedtofastensteelpartswithsquare
punchedholes.
ACarriageBoltisthemostcommontypeof
round-headedbolttobeusedwhenworkingwith
wood.
APlowBolt hasaflat,taperedheadthatfits into
acountersunkhole –primarily usedwith metalparts.
Usedinthemarineindustryfor attaching
cuttersandotherpartsto dredges.
Plow Bolt
Carriage Bolts

19. StoveBoltsareavailablewiththesametypesof
headdesignsaswoodscrews,indiametersfrom
5/32”to1/2”andin lengthsfrom3/8”to6inches.
Studsareanothertypeofthreadedfastener,whichhaveno
headatall andis merelyasteelrodwith threads onbothends.
Oneendisscrewedintoapart,otherpartsare
assembledoverthestuds andscrewedin place withanut.

20. Other “ Bolts”
Somefastenersarereferredtoasbolts
butareactually screws.
ALagBoltisreallya“heavy-dutyscrew”
withasquareorhexhead.
Designedtobedrivenwithawrench.
Availableinlengthsfrom1”to6”anddiameters
from1/4”to 1/2”.
AHangerBoltisafastenerthathaswoodscrewstyle
threadsononeendandmachinethreadsontheother.
Noheadonthistypeof“bolt”.
Designedtobeahiddenfastener.

21. Threads–Externalhelicalribsonthebodyofaboltattheendopposite
thehead.
Thediameterofaboltisdeterminedbythediameterofthecrestofthe
threads.
Thelengthofmostbolts(ormachinescrews)isdeterminedbythe
measuringfromthebottomoftheheadtotheendof thethreads.
Flatheadbolts aremeasuredfromthethreadedendto thetopofthehead.
TheHeadSizedetermineswhatsizewrenchorsocketmustbeusedto
turnorholdtheboltor nut.
Asquareorhexagonalbolt headis measuredacrossthe“flats”.
Example–A¾”wrenchisneededtoturna½”diameterbolt head.
Sizes and Descriptions

22. Threads
Threads–Externalhelicalribsonthebodyofabolt.Usuallya
bolt“mates”withinternalthreadsofanut.
Thetopoftherib is calledthe crest,orthread tip.
Bottomofthegrooveiscalledthethread root.
Threadsaremeasuredbycountingthenumberperinch.(Metric
threads aremeasuredbythedistance betweenthreads – pitch–in mm)
Thread gauges are available that match
threads against those on the gauge.

23. Thetypeofthreadsthatareusedformostapplicationsare
coarsewithdeep grooves.
Somethreadsarefiner,withshallowergrooves.
Boltswithfinethreadsareusedonlyunderspecialconditions–such
aswhenthepartsbeingfastenedhavethin walls.
Boltsandscrewsnormallyhaveright-hand threads.
Turnedtotheright(clockwise)whentightened.
Occasionally,bolts,screwsandnutswithleft-hand threads
areneeded.
Turnedtotheleft (counter-clockwise)whentightened.

24. American National Standards Institute
( ANSI )
Therearecarefullycontrolledstandardsforthreading
boltsandnuts.
ANSIestablishessuchthingsastheangleofthreads,
thedepthoftherootandthemanufacturing tolerances
(fit) whicharereferredtoasthe“Unified ScrewThread
Standards”.

25. International Organization for Standardization
( ISO )
Establishedstandardsforclassifyingmetricboltsand
screws.

26. GradesandHeadMarkings–Inch-Series
Thekindofsteelboltsandscrewsaremadeofandthe
treatmenttheyreceiveduringmanufacturedeterminetheir
strength.
TheSocietyofAutomotiveEngineers(SAE)has
establishedstandardsforclassifyinginch-seriesboltsand
screwsintogrades,basedontheirtensile strength.
Markingsconsistofradial “slashes”.
High-qualityinch-seriesboltsandscrews¼”andlargerhave
them.
Grade5or better hardwareshouldbeusedin mostsituations.

28. GradesandHeadMarkings- Metric
Thekindofsteelboltsandscrewsaremadeofandthe
treatmenttheyreceiveduringmanufacturedeterminetheir
strength.
The International Organization for Standardization (ISO)
hasestablished standardsfor classifying metric bolts and
screwsintopropertyclassesbasedonstrength.
Numbersontheheadindicateproperty class.
High-qualitymetricboltsandscrews4mmandlargerhave them.
Class8.8or better hardwareshouldbeusedin mostsituations.

30. Nuts and Washers
Nuts have coarse or fine internal threads that correspond to
thethreadsof abolt andaredesignedto “screw”ontothebolt
tofastenit in place.
Agreatvarietyofshapesandsizesforstandardandspecial
applications.
Threadsperinchordistancebetweenthreadscanbedetermined
withathreadgaugejustlikebolt threads.
Nutshavethreeimportant dimensions:
Thickness
Distanceacrossthe flats
Inside diameter(sameasthatof thebolt with whichit is tobeused).

31. HexandSquare Nuts
Themostcommon
nuts,generallymadeof
steelandarehexagonal
orsquarein shape.
JamNuts–Usedtolockathreadedpartin place.
CastellatedandSlottedNuts–Secureanutinplacesoit
can’tpossiblycome loose.
Self-LockingNuts–Stayfirmlyinplaceevenwithconstant
vibration.
Manyothertypesofnuts availableforspecialuses.

32. Aplainwasherissimplyasteeldiskwithahole
throughthe center.
Like bolts and nuts the maybemanufactured with a
varietyofdifferent materials
They help distribute the load over an area larger than
the headof the bolt or nut, thus reducing the stresses
thatwouldotherwise exist.
Plainwashersareidentifiedbytheiroutsidediameter
andthediameterofthehole,whichistheboltsize
ratherthantheactualdiameterofthehole.
Thewasherthicknessvarieswiththesizeofthe
washer.

33. Lockwashersarefrequentlyusedtokeepnutsand
 boltstight,especiallywhentheyaresubjectto vibration.
 HelicalSpringWashers–Madeoftoughspringsteel.
Theyaresplitandoneendofthesplitisbentup.Whenthenut
istightened,thesectionofthewasherthatisbent up“bites”
intothenutandthefastenedpart.
 ToothedLockWashers–Hasmanysharp,heat- treated
teethtodigintothesurfacespressingagainstit.
 Manyothertypesofwashersareavailableforspecial uses.