Types and Uses of Fasteners
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Importance of Fasteners
• They simplify the manufacture of
machines and structures.
• They reduce the need for large one piece
parts.
• It is normally easier to make less complex
components and fasten them together
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Importance cont.
• They simplify repair of structures and
equipment.
• Individual component parts can simply and
quickly be separated for inspection, repair,
or replacement.
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They Provide Safety
• Use of fasteners tends to assure that once
an assembly is fastened together it will
hold together.
• They can also be installed to provide
additional support or they be a weak links.
(Ex. Shear pins, drive shafts, & breakaway
plowshares)
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B. General types of
Fasteners
• Bolts, nuts, and
washers
• Screws
• Keys
• Studs
• Pins
• Rings
• Rivets
• Adhesives
• Nails
• etc.
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Specific Types and uses of
fasteners
• Bolts: are threaded lengths of steel rod
with heads on one end.
• They are used with a nut at the other end
and sometimes with a washer as well.
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American Standard Bolts
Hexagon or Square Head
• Most have a hexagonal head (6-sided). Older
square bolts have a 4- sided head.
• Without a nut they are called cap screws and
are screwed into threaded holes.
• Bolts are selected by strength rating,
chemical or heat compatibility.
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Carriage Bolts
• Most have a round head with a square
neck, under the head.
• Carriage bolts are used to fasten wood
parts where a smooth finish is required.
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Bolts
Carriage
bolt
Plow
bolt
Cap
Screw
Hex
Bolt
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Plow Bolts
• Counter sunk, square- neck carriage bolt.
• These have a flat, tapered head that fit
into countersunk holes.
• Used when it is necessary for the head to
lie flush with the surfaces of the part.
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Nuts:
• Are flat, usually hexagonal shaped steel
pieces with internally cut threads.
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Castellated & Slotted nuts
• A. These are used when a cotter pin is
placed through a hole in the bolt to secure
the nit so it cannot come loose.
• Ex: Wheel bearing spindles
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Nuts
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Self Locking nuts
• A. Once tightened these nuts stay firmly in
place.
• B. They are commonly known as “elastic”
or plastic insert nuts.
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Washers
• A. Plain washers: (flat washers) are steel
disks with a hole in the center.
• B. They are used to reduce the stress
under the bolt or nut.
• C. They spread a clamping force from the
bolt over a larger area to span slots and
oversize holes in wood
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Washers
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Lock Washers
• A. Helical spring washers are made of
tough spring steel.
• B. Normally installed under the nut or bolt.
• C. They are used to prevent rotation of the
nut.
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Nails
• Nails are steel rods with a head on one
end and usually pointed at the other end.
• They are used primarily to join wood
together.
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Nail size:
• Generally given in terms of “penny”
• “d” indicates the penny size
• Nails are sold by the pound at most
hardware stores.
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Penny Sizes
Number per pound
Penny
2d
3d
4d
8d
10d
16d
20d
Length (In)
1
1¼
1½
2
3
3¼
4
Common
830
578
316
168
106
69
49
Box
8010
635
473
236
145
84
71
Finish
13151
807
584
309
189
121
90
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Common Nail
• This is a general all purpose construction
nail suitable for framing structures.
• It has a larger diameter than the same size
box nail
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Common Nail
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Box Nail
• Box Nail are used for end nailing and light
household use.
• The point is dulled to prevent splitting the
wood
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Box Nails
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Finish Nail
• This is a nail with a small head with a
dimple in the center to allow for
countersinking with a nail set.
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Finish Nail
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Duplex Nails
• A duplex nail has two heads on the shank
• It is used to whenever a nail has to be
removed.
• Ex when assembling concrete forms
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Duplex Nail
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Roofing Nails
• Used to secure shingles or roofing to the
underlying structure
• They are normally available with either a
spiral or helix head shank for extra holding
power.
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Roofing Nail
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Screws
• Screws are threaded lengths of steel rod
with heads on one end.
• Screw heads may be slotted, cross
slotted, square, or hexagonal.
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Types of screws
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(c) 2006 Texas Trade & Industrial
Education
UNT in partnership with TEA, Copyright ©. All rights
reserved. Building Trades: Fasteners