1. An Aerospace Manufacturing Perspective Introduction to Fastener Technology Part 3 1

2. Fasteners in Aviation Permanent Fastening Discussed previously Temporary Fastening Threaded Non-Threaded 2

3. Temporary Fastening Threaded – Bolts – Studs – Screws Non - Threaded 3

4. Temporary Fastening 4 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 5

6. Threaded Fasteners 6 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. 7

8. Thread Terminology Crest – Peak edge of thread Root – Bottom of thread cut into a cylindrical body Thread angle – Angle between threads faces 8

9. Thread Terminology Major diameter – Largest diameter on an external or internal thread Minor diameter – Smallest diameter on an external or internal thread 9

10. Thread Terminology Pitch – Distance between crests of threads 10

11. Types of Thread Form Profile shape of the thread 11

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: M8×1.25 12

13. Thread Drawings For simplified representation, use thick and thin continuous lines for representing crests and roots respectively : 13

14. Bolt Terminology Bolt is a threaded cylinder with a head 14

15. Bolt Application 15

16. Bolt Application - Engine 16 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. 17

18. Screws Application 18

19. Screws Application - Fuselage 19 Countersunk screws are flush with the skin on this Cessna 310R

20. Screws Application - Engine 20 Exhaust shroud screws on an IO-320 engine

21. Stud Terminology 21

22. Stud Application 22