Fastners

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Fasteners
Used to join together the various parts

• Spot Welding
• Soldering
• Nuts Bolts
• Washers
• Screws
• Clips
• Clamps
• Studs
• Rivets
• Studs
• Splines/Keys/RollPins
• Glue/Silicone/Adhesives
• Crimped (Body seams, electrical connections)

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Fasteners
External Threads (Male Threads)

• Bolts, Studs, Screws

Internal Threads (Female Threads)

• Nuts, Threaded holes

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Nuts
Hex Nut Most common on automobiles.
Castle Nut locks with a cotter pin
Wing Nut No tool required
Locking Nut Nylon Patch (center, top)
Lug Nut Taper face to help center the wheel
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Fasteners
Metric Threaded Fasteners

• ISO Metric International Organization for
  Standardization

• Most new vehicles have metric fasteners

• M6, M7, M8, M10, M12, M14

M8 X 25 X 1
8mm
Metric
Pitch (threads are 1mm apart)
25mm long
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Screws
Machine Screws no nut required ( usually less
then ¼ Passes through one piece and threads
into other.
Sheet Metal Screws(self tapping) makes its own
hole/threads
Set Screw (allen wrench/no head) Used for
aligning pullies on the shaft.
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Washers
Flat Washer Distributes pressure over a wider
surface area.
Lock Washer - Prevents the fastener from
loosening. Used at high
vibration places. Bites
into the material and the fastener.
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Some common screw and bolt head type
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Nut and Washer
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Fasteners
Circlips

• External

• Internal

Snap Ring Pliers
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Thread Pitch is measured with a special gauge
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The correct gauge will match the grooves of the
bolt
12
This gauge has a the same thread pitch as the bolt
13
This gauge has a different thread pitch than the
bolt
14
Same Pitch
15
Different Pitch
16
These gauges can measure the diameter, pitch and
bolt length
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LOCK NUTS
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How do fasteners lock in place?

• Cotter pins, locking tabs, and self locking
  nutsare often used.

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How do fasteners lock in place?

• Proper torque is usually the only thing that
  keeps a bolt or nut from vibrating loose
• Sometimes lock washers are used, especially when
  a light fastening torque is desired
• Over-tightening a lock washer will ruin its
  ability to hold

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Thread Terminology

• Crest Peak edge of thread
• Root Bottom of thread cut into a cylindrical
  body
• Thread angle Angle between threads faces

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Thread Terminology

• Major diameter Largest diameter on an external
  or internal thread
• Minor diameter Smallest diameter on an external
  or internal thread

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Thread Terminology

• Pitch Distance between crests of threads

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Thread Standard

• A metric ISO screw thread is designated by the
  letter M followed by the value of the nominal
  diameter D and the pitch P, both expressed in
  millimeters and separated by the multiplication
  sign .
• Example M81.25

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Thread Drawings
For simplified representation, use thick and thin
continuous lines for representing crests and
roots respectively
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Bolt Terminology

• Bolt is a threaded cylinder with a head

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Bolt Application
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Screw Terminology

• Screw is similar to bolt, but has a longer thread
  than a bolt
• Bolted joint is usually created by turning a nut
  screw is installed by turning it.

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Screws Application
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Stud Terminology
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Stud Application