1. Mechanical Engineering Drawing MENG 204
Fasteners & shafts
Summer Semester 2015
By:
Dr. Ghassan Mousa

2. Thread standards & definition
Threaded fasteners
Used to non-permanently join one or more objects
together.
Thread standards & definition
d: major diameter
p: pitch
l: lead
Multiple threads
Die for external threading.
Tab for internal threading
Fig. 8.1 Terminology of screw threads

3. Types
Three types of threaded fastener. (a) Bolt and nut; (c) Cap screw; (c) stud.

4. Metric thread Thread angle is 60˚ M8 × 1.25 Imperial thread
3/8 – 24 UNF
Table 8-1 Geometrical data for Standard Bolts (SI)

5. Power screw Trapezoidal thread Thread angle is 30˚ Tr 36 X 10
Buttress Thread
S 40 X 7
Loading Direction

6. Strength Bolts in axial loading fail at the: Fillet under the head.
Thread runout.
1st thread engaged in the nut.
Table 8-11 Material properties of steel bolts

7. Setscrew
washer
Nuts
Slotted nut jam nut
Prevailing torque
locknut

8. Design (Configuration)

9. Design (Head Style)

10. Design (Drive Type)

11. Thread dimension Threaded Fasteners Preferred Sizes (Length):
2, 3, 4, 5, 6, 8, 10
12, 16, 20, 25, 30
35-60, 65, 70, 80
90-140, 150, 160, 180, 200

12. Shafts Stepped shaft Used to transmit power (torque).
The shorter the better.
Load carrying components should be placed near the bearing.
Means of transmitting power through:
Gears
Belts
Chains
Torque is transmitted by using keys
Axial force is supported by using Pins
Stepped shaft

14. Retaining rings
E ring
External ring

15. Keys
Woodruff key
Tapered key
Gib head tapered key

16. Pins
Spring pin
Hairpin cotter
Dowel pin
Cotter pin
Tapered pin