This document discusses different types of fasteners and fastening methods. It describes threaded fasteners like bolts, screws, and nuts. It defines screw thread terminology and profiles of common thread types. It explains characteristics of bolts and nuts like chamfering, washer facing, and counter-sinking. Methods for drawing hexagonal and square head bolts and nuts are also presented. The document provides details on different threaded fastener components and their uses to fasten and join parts in machines and structures.

2. 2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
2-10
2-11
2-12
nuts
2-13
2-14
2-15
Fasteners and Fastening
Threaded Fasteners
Screw and Screw Thread
Screw Thread Terminology
Basic Profiles of Screw Threads
Types of V-threads
Profile of Square Thread and its modifications
Right-Hand and Left-Hand Threads
Single-start and Multi-start Threads
Bolts and Nuts
Chamfering of Bolts and Nuts
Washer facing of the hexagonal bolts and
Counter-sinking of the nut
Method of drawing hexagonal head bolt and nut
Method of drawing a square head bolt and nut

3. A mechanical element which holds two or more parts of a machine
or a structure is known as fastener. The process is called fastening.
Permanent fastening: it involves destruction during separation
 press fits
 shrink fits
 rivets
 welding, brazing, and soldering
 adhesives
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4. Temporary fastening: it doesn’t involve destruction during
separation
 Bolts and nuts
 studs and nuts
 screws
 keys
 pins, etc…

5.  Externally threaded fasteners
 Internally threaded fasteners

6. Use:
 to fasten parts together
 for the relative adjustment of the adjacent parts
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7.  To transmit motion and
power
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8. Lead=L=n p
n = number of start
Figure 2-1
Terminology of screw
threads. Sharp Vee
Threads shown for clarity;
the crests and roots are
actually flattened or
rounded during the
forming operation

9.  V-thread
 Square thread

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12.  Right-hand thread – A screw thread that is screwed in by rotating CW .
 Left-hand thread – A screw thread that is screwed in by rotating CCW.

13. (a) Single (STANDARD)
(b) double
(c) triple threaded

14. 2-10 Bolts and Nuts
Bolt . Threaded
fastener designed to
pass through holes in
mating members and
to be secured by
tightening a nut from
the end opposite the
head of the bolt.

15. 2-11 Chamfering of Bolts and
Nuts

16. 2-11 Chamfering of Bolts and
Nuts

17. 2-12 Washer facing of the hexagonal
bolts and nuts
Finished vs.
Unfinished Bolts:
The difference between a finished and
Unfinished hex head bolt is a washer
Under the head of the finished bolt.

18. 2-13 Counter-sinking of the nut
Countersinking of nut
facilitates the gripping
of the bolt end when
the nut first enters
while it is threaded on

19. 2-14 Method of drawing
hexagonal head bolt and nut

20. 2-14 Method of drawing
hexagonal head bolt and nut
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21. 2-14 Method of drawing
hexagonal head bolt and nut

22. 2-14 Method of drawing
hexagonal head bolt and nut

23. 2-15 Method of drawing a square
head bolt and nut

24. 2-15 Method of drawing a square
head bolt and nut

25. 2-15 Method of drawing a square
head bolt and nut

26. Conventional
representation
s of threads

37. 2.17.Locking of nuts

47. 2.21 Foundation bolts