Basic Mechanical Fasteners

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BasicMechanical Fasteners

• TED126

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mechanical fastenersChoosing

• The choice of a fastener is dependent
• on the design requirements and the
• environment in which the fastener will be used.

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mechanical fastenersChoosing

• Attention to various aspects of the fastener must
  be considered. Some of these are listed below
• Function of the fastener
• Operating environment of the fastener
• Type of loading on the fastener in service
• Thickness of materials to be joined
• Type of materials to be joined
• Configuration of the joint to be fastened

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mechanical fastenersChoosing

• The choice of the correct fastener may simply
  entail fulfilling a requirement for strength
  (static or fatigue) or for corrosion resistance.
  
• Conversely, the choice may be constrained by a
  complex set of requirements.
• The scope and complexity of the fastener system
  required is frequently determined by the
  consequences of fastener failure.

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mechanical fastenersChoosing

• One method of guarding against failure of a new
  fastener in a critical application is to
  sufficiently test the fastener system prior to
  use.
• A designer must be careful when extrapolate
  existing data to an increased size of the same
  fastener,
• because larger-diameter fasteners can have
  considerably lower fatigue endurance limits than
  smaller-diameter fasteners.

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mechanical fasteners

• Is the Zipper a fastener? .hmm
• What two simple tools make up the zipper?
• Wedge
• door stop and a plow
• Simple machine - incline
• Hook
• The zipper was patented on August 29, 1893
• by Whitcomb Judson, a Chicago mechanical
  engineer.
• The paper clip is considered a fastener.
• 1867

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mechanical fasteners Functions

• To hold parts together.
• To hold a completed product to a
• wall, floor or other parts of a building or
  object.

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mechanical fasteners Types

• Non-threaded
• Threaded

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mechanical fasteners Non-threaded

• Four Major Types
• Nails
• Rivets
• Staples
• Special fasteners
• Cotter pin
• Corrugated fasteners
• Glazing pins
• Skotch fasteners

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Four Major Types mechanical fasteners
Non-threaded

• Nails
• Hand made nail
• 18th century
• Cut nail
• 1790 to 1900
• Wire nail
• Nails provide one of the best clues to the age of
  historic buildings, especially those constructed
  during the nineteenth century, when nail-making
  technology advanced rapidly.

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Four Major Types mechanical fasteners
Non-threaded

• Nails
• What simple machine is associated to the nail?
• Wedge
• Other examples knives, axes and forks
• How many incline planes does a nail have?
• Two
• When a hammer pulls a nail out of the object
• What are the two simple machines at work?
• Wedge and lever

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Four Major Types mechanical fasteners
Non-threaded

• Nails
• Nails go back at least to the Roman period.
• Nails are usually sold by weight (either in bulk
  or in boxes).
• In the US, the length of a nail is designated by
  its
• penny size (d) from the head to the point.
• It is commonly believed that the origin of the
  term "penny" in relation to nail size is based on
  the old custom in England of selling nails by the
  hundred.
• A hundred nails that sold for six pence were "six
  penny" nails.

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Four Major Types mechanical fasteners
Non-threaded

• Nails
• Nails go back at least to the Roman period.
• Nails are usually sold by weight (either in bulk
  or in boxes).
• In the US, the length of a nail is designated by
  its
• penny size (d) from the head to the point.
• Ranges from 2d to 60d.
• Anything larger than 10d is referred to as a
  spike.
• It is commonly believed that the origin of the
  term "penny" in relation to nail size is based on
  the old custom in England of selling nails by the
  hundred.
• A hundred nails that sold for six pence were "six
  penny" nails.

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Four Major Types mechanical fasteners special

• Nails
• HurriQuake Nail (2005-2006)
• The features of the nail are
• designed primarily to provide more
• structural integrity,
• especially against the forces of
• hurricanes and earthquakes.
• Special high-carbon alloy

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Four Major Types mechanical fastenersspecial

• Nails
• HurriQuake Nail (2006)
• Tests at the Clemson Wind Load Test Facility
  confirmed what had already been stated.
• With equipment to simulate the force of winds,
  roofs attached with traditional nails were pulled
  apart at around 13,500 pounds of force.
• At forces up to 16,000 pounds, walls built with
  the HurriQuake environment nail showed minimal
  wall movement.
• As the test rig pushed 20,000 pounds, the maximum
  it was capable of testing, showing that the
  HurriQuake environment nail sustained 20,000
  pounds of force and still was not sheared or
  completely pulled out.

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Four Major Types mechanical fasteners special

• Nails
• HurriQuake Nail (2006)
• ..sustained 20,000 pounds of force
• and still was not sheared
• or completely pulled out.

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Four Major Types mechanical fasteners
Non-threaded

• Common Nails
• Common nails have
• larger nail shank diameters than other nails.
• Common nails are
• thicker than box, cooler or sinker nails and are
• therefore strongest and stiffest.
• Common nails are
• always specified for shear wall panels.

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Four Major Types mechanical fasteners
Non-threaded

• Common Nails
• Used for most medium to heavy construction work,
  this type of nail has a thick head and can be
  driven into tough materials.
• Common nails are made from wire and cut to the
  proper length and are available in sizes 2d
  through 60d.

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Four Major Types mechanical fasteners
Non-threaded

• Finish Nails
• Finishing nails have rounded heads that can be
  driven flush with the surface of the wood (3d to
  10d).
• Although they are often countersunk like casing
  nails, they can be used without countersinking.
• Brads are recommended for light assembly work
  where the head should be concealed (.5 to1.5).
  Brads look like miniature finishing nails.
• They are thinner, shorter, and smaller than
  finish nails.
• Escutcheon pins - 3/16 to 2.0- Round smooth
  shank, a diamond point and an oval head. Made in
  both brass and steel.

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Four Major Types mechanical fasteners
Non-threaded

• Casing Nails
• These nails are used where the nailhead must be
  hidden.
• They have small heads and smaller diameters than
  common nails.
• Casing nails have a conical head, sometimes
  cupped, and are somewhat thicker than a finishing
  nail. A body of a common nail and head like a
  finish nail.
• They are sometimes sold already painted and are
  used to attach trim.

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Four Major Types mechanical fasteners
Non-threaded

• Box Nails
• a nail having a long shank, smooth or barbed,
  with a sharp point and a flat head.
• Box nails are designed for light construction and
  household use.
• Sometimes coated with cement, rosin or galvanize
  to hold better.

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Four Major Types mechanical fasteners
Non-threaded

• Rivets
• To secure two or more pieces of material
  together, a rivet is placed into a hole cut just
  a bit larger in diameter than the rivet itself.
  Materials - steel, plastic, aluminum,
  nickel-copper, copper and stainless.
• Steel - Use steel rivets for very heavy duty jobs
  and when riveting steel to steel.
• Tinners - are solid steel rivets with either a
  tin or zinc finish. They are typically used in
  sheet metal fabrication.
• Pop Rivet - A type of rivet that is installed
  with a tool that pulls a mandrel through the
  rivet body performing the riveting function and
  then snaps off giving a "popping sound".
  Sometimes referred as a blind rivet

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Four Major Types mechanical fasteners
Non-threaded

• Staples
• Staples are U-shaped metal fasteners that are
  driven into a surface to hold or secure an object
  in place.
• Staples include flat crown and rounded crown
  styles.
• Flat crown staples have flat top or crown and are
  used for general fastening.
• Rounded crown staples have a curved top and are
  used to secure wire, tubing, and other rounded
  items to flat surfaces.
• Staples are available in different sizes,
  lengths, styles, and materials.
• Fastest growing non-threaded fastener.

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Four Major Types mechanical fasteners
Non-threaded

• Special
• Cotter pin (cotter key) - Typically made of wire
  with a half-circular cross section.
• Once inserted, the two ends of the pin are bent
  apart, locking it in place.
• In order to facilitate the initial separation of
  the tines, one tine of the cotter pin is often
  noticeably longer than the other.

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Four Major Types mechanical fasteners
Non-threaded

• Special
• Corrugated fasteners - a small strip of
  corrugated steel with sharp points on one side
  hammered across wood joints in rough carpentry.

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Four Major Types mechanical fasteners
Non-threaded

• Special
• Glazing pins - an old method of holding glass in
  a sash prior to glazing the window.
• Skotch fastener - wood fastener

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Four Major Types mechanical fasteners
Non-threaded

• Three ways to install a Nail
• Pound with a hammer
• Powder actuated tools - means a device for making
  instantaneous forced entry into materials by use
  of a tool, a fastener and an explosive load.
• .22 caliber shot
• .27 caliber shot
• .38 caliber shot
• Power
• Electric
• Gas
• Pneumatic Air
• Different types of power nailers
• roof, framing, finish, brad, stapler
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