Fasteners in Aviation

1
Introduction to Fastener Technology Part 3
An Aerospace Manufacturing Perspective
2
Fasteners in Aviation

• Permanent Fastening
• Discussed previously
• Temporary Fastening
• Threaded
• Non-Threaded

3
Temporary Fastening

• Threaded
• Bolts
• Studs
• Screws
• Non - Threaded

4
Temporary Fastening

• some common aircraft fasteners organized by
  part number

5
Threaded Fasteners

• Use to hold parts together
• Unlike any other fasteners, threaded fasteners
  are able to move part(s) relative to others

6
Threaded Fasteners

• Bolts connecting two sections of a PW4098
  Turbofan engine

7
Thread Terminology

• External (male) thread Thread cuts outside of
  the cylindrical body.
• Internal (female) thread Thread cuts inside of
  the cylindrical body.

8
Thread Terminology

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

9
Thread Terminology

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

10
Thread Terminology

• Pitch Distance between crests of threads

11
Types of Thread Form

• Profile shape of the thread

12
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

13
Thread Drawings
For simplified representation, use thick and thin
continuous lines for representing crests and
roots respectively
14
Bolt Terminology

• Bolt is a threaded cylinder with a head

15
Bolt Application
16
Bolt Application - Engine

• Engine case bolt and nut on a Lycoming IO-320
  engine
• Nut is on the left hand side, bolt head is on
  the right

17
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.

18
Screws Application
19
Screws Application - Fuselage

• Countersunk screws are flush with the skin on
  this Cessna 310R

20
Screws Application - Engine

• Exhaust shroud screws on an IO-320 engine

21
Stud Terminology
22
Stud Application