Date of Revision: 2/17/2016
Introduction to Fastener Technology Lecture Notes, Part 3
Teaching Module Outline on
Fasteners in the Aerospace Industry:
Introduction to Fastener Technology,
Part 3
Lecture Notes
(Slide 2)
Fasteners in Aviation

Permanent Fastening
o Discussed previously

Temporary Fastening
o Threaded
o Non-Threaded
(Slide 3)
Temporary Fastening
 Threaded and Non-Threaded
o Threaded : Bolts, Studs & Screws
(Slide 4)
Threaded Fasteners
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Date of Revision: 2/17/2016
Introduction to Fastener Technology Lecture Notes, Part 3
 Like any other fasteners, threaded fasteners are used to hold parts together. However,
unlike any other fasteners, threaded fasteners are able to move part(s) relative to others.
(Slide 5)
Thread Terminology
External thread
Internal thread

External (male) thread: Thread cuts outside of the cylindrical body

Internal (female) thread: Thread cuts inside of the cylindrical body
(Slide 6)
Thread Terminology
External Thread
Internal Thread
Thread angle
Crest
Root
Root
Crest

Crest – Peak edge of thread

Root – Bottom of thread cut into a cylindrical body

Thread angle – Angle between threads faces
(Slide 7)
Thread Terminology
Minor dia.
2
Major dia.
Internal Thread
Major dia.
Minor dia.
External Thread
Date of Revision: 2/17/2016
Introduction to Fastener Technology Lecture Notes, Part 3

Major diameter – Largest diameter on an external or internal thread

Minor diameter – Smallest diameter on an external or internal thread
(Slide 8)
Thread Terminology
External Thread
Internal Thread
Pitch
Pitch

Pitch – Distance between crests of threads
(Slide 9)
Types of Thread Form
Example :
“knuckle thread form”

Types of thread form – Profile shape of the thread
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Date of Revision: 2/17/2016
Introduction to Fastener Technology Lecture Notes, Part 3
(Slide 10)
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: M8×1.25
Nominal
size
M6
M8
M10
M12
Major
diameter
Pitch
Minor
diameter
Tap drill size
6.00
8.00
10.00
12.00
1.00
1.25
1.50
1.75
4.92
6.65
8.38
10.11
5.00
6.75
8.50
10.00
Metric thread
Minor diameter ≈ Tap drill size
(Slide 11)
Thread Drawings

Detailed Representation
o For detailed representation, crest and roots are drawn using slanting lines or in
V shape
External thread
Internal thread
Thread runout
Pitch

60o
Schematic Representation
o For schematic representation, use alternate long and short lines for
representing crests and roots respectively
External thread
Thread runout
Pitch
60o
4
Internal thread
Date of Revision: 2/17/2016

Introduction to Fastener Technology Lecture Notes, Part 3
Simplified Representation
o For simplified representation, use thick and thin continuous lines for
representing crests and roots respectively
External thread
Internal thread
Thread runout
Pitch/2
Root
Crest
(Slide 12)
Bolt Terminology

Bolt is a threaded cylinder with a head
Thread length
Length
Hexagonal head
Width
across flat
bolt and nut
Head
thickness
(Slide 13)
Bolt Application
2. Insert a washer.
3. Screw a nut.
1. Insert a bolt into
a clearance hole
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Date of Revision: 2/17/2016
Introduction to Fastener Technology Lecture Notes, Part 3
(Slide 14)
Screw Terminology

Screw Terminology & Application
o Screw is similar to bolt, but has a longer thread than a bolt
o Bolted joint is usually created by turning a nut; screw is installed by turning it.
(Slide 15)
Screw Application
1. Drill a hole.
x drill,
CSK to y
x drill, w deep,
CSK to y
Draw 90o
y
(Slide 16)
Stud Terminology

Studs
Thread length
Thread length
Drawing
representation
Length
6
2. Place the screw.
Date of Revision: 2/17/2016
Introduction to Fastener Technology Lecture Notes, Part 3
(Slide 17)
Stud Application
1. Drill a hole.
2. Tap a hole.
3. Screw a stud.
4. Place the part to be
fastened.
5. Insert washer and
fastened a nut.
Review of
Fasteners in the Aerospace Industry:
Introduction to Fastener Technology
At the conclusion students should be able to:
 Demonstrate an understanding of the different types of fastening:
permanent and temporary
 Demonstrate an understanding of thread terminology such as
external and external thread, and pitch
 Demonstrate an understanding of thread drawings terminology
such as detailed, schematic, and simplified representations
 Demonstrate an understanding of bolt terminology and application.
 Demonstrate an understanding of stud terminology and application.
 Demonstrate an understanding of screw terminology and
application.
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