Fasteners (Aircraft Rivets)

• Category B1 and B2 Licences

  Aircraft Maintenance Licences
• Aircraft Materials


  • Aluminium
  • Corrosion-Resistant Steel
  • Monel
• Fasteners


  Aircraft Rivets
• Rivet


  Any type of fastener that obtains its clamping action by having one of its ends mechanically upset
• Rivet Specification Systems


  • AN - Air Force-Navy

  NAS - National Aerospace Standard

  MS - Military Standards
• Solid-Shank Rivets


  The single most commonly used aircraft fastener, available in a variety of materials, head designs and sizes

  
• Rivet Codes


  Indicate rivet size, head style and alloy material

  
• Rivet Codes


  • First part - numbering system

  Second part - head style

  Third part - alloy material code

  Fourth part - shank diameter

  Fifth part - length

  
• Universal Head Rivets


  Measured from bottom of head to end of shank

  
• Countersunk Rivets


  Measured from top of head to end of shank

  
• Rivet Head Designs


  • Universal and Countersunk/Flush
• Countersinking


  Process of cutting away metal in top sheet to accommodate rivet head
• Dimpling


  Process of mechanically 'denting' sheets to accommodate rivet head
• Rivet Alloys


  • 1100 Aluminium (A)

  2117 Aluminium Alloy (AD)

  5056 Aluminium Alloy (B)

  2017 Aluminium Alloy (D)

  2024 Aluminium Alloy (DD)

  7050-T73 Aluminium Alloy (E)

  Corrosion-Resistant Steel (F)

  Monel (M)
• 1100 Aluminium (A) Rivets


  Made of pure aluminium, used for non-structural applications
• 2117-T3 Aluminium Alloy (AD) Rivets


  Most widely used, high strength and shock-resistance, no heat treatment required
• 5056 Aluminium Alloy (B) Rivets


  Used on magnesium structures to prevent dissimilar metal corrosion
• 2017 Aluminium Alloy (D) Rivets


  Extremely hard, must be heat treated before use, often called 'icebox rivets'
• 2024 Aluminium Alloy (DD) Rivets


  Also called 'icebox rivets', must be stored at cool temperatures until ready to drive
• 7050-T73 Aluminium Alloy (E) Rivets


  High strength, corrosion-resistant alloy
• Corrosion-Resistant Steel (F) Rivets

  Used where corrosion resistance is required
• Monel (M) Rivets


  Nickel-copper alloy with high corrosion resistance
• Rivet Heat Treatment


  Required for some alloys to maintain strength
• Special Rivets and Fasteners

  • Blind Rivets

  Friction-Lock Rivets

  Mechanical-Lock Rivets (Huck-Loks, Olympic-LOKs, CherryMAX)

  Hi-Shear Rivets

  Hi-Loks

  Jo-Bolt Fasteners

  
• Special Rivets and Fasteners

  • Used where access is limited or for specific applications

  
• Removal of special fasteners requires specific techniques
• 1. rivets


  Rivets made of 2017 aluminium alloy that can be kept in an annealed condition by removing them from a quench bath and immediately storing them in a freezer
• DD-rivets


  Rivets made of 2024 aluminium alloy that are identified by two raised dashes on their head and must be stored at cool temperatures until they are ready to be driven
• 7050-T73 aluminium alloy (E-rivets)


  Aluminium alloy containing zinc as the major alloying ingredient and is precipitation heat-treated, identified by a raised circle on the rivet head
• Corrosion-resistant steel (F-rivets)


  Stainless steel rivets used for fastening corrosion-resistant steel sheets, with no marking on their heads

  
• Monel (M-rivets)


  Rivets identified by two recessed dimples in their heads, used in place of corrosion-resistant steel rivets when their somewhat lower shear strength is not a detriment

  
• Rivet heat treatment


  1. Natural ageing (cooling at room temperature)

  2. Precipitation heat-treatment (applying a slightly elevated temperature for an extended period)
• Blind rivets


  Special rivets that can be installed with access to only one end of the rivet, more expensive than solid-shank rivets
• Friction-lock rivets


  • Consist of a shell and mandrel/pulling stem, the stem is pulled until the header forms a bucktail on the blind side and the stem breaks off
• Mechanical-lock rivets


  • Permanently lock the stem into place so vibration cannot shake it loose, include Huck-Loks, Olympic-Loks, and CherryMAX
• Hi-Shear rivets


  Have the same strength characteristics as a standard AN bolt, secured by a crushed collar instead of a nut
• Hi-Lok fasteners


  Manufactured in several different alloys, possess sufficient strength to withstand bearing and shearing loads, installed with a shear collar

  
• Jo-Bolt fasteners


  Patented high-strength structural fasteners used in close-tolerance holes where strength requirements are high but physical clearance precludes the use of standard bolts

  
• Removal of special fasteners


  1. Remove washer-nut or locking collar, tap remaining fastener out of hole

  2. For flush-type Jo-Bolts: drill pilot hole, drill to depth of pilot hole, drive remainder of shank and blind head from hole