1. Threads, Fasteners & Springs

2. Use of Screw Threads To hold parts together
To adjust parts with reference to each other
To transmit power

3. Screw Thread Terms

4. Important Terms
PITCH: The distance from a point on a screw thread to a corresponding point on the next thread measured parallel to the axis. The pitch P is equal to 1 divided by the number of threads per inch.
LEAD: The distance a screw thread advances in one turn.
Thread Form: The cross section of thread cut by a plane containing the axis.

5. Screw Thread Forms

6. Thread Pitch

7. Right Hand & Left Hand Threads

8. Single & Multiple Threads

9. Thread Symbols
There are three methods of representing screw threads on drawings:
Detailed
Simplified
Schematic

10. Detailed Thread Symbols

11. Simplified Thread Symbols (External Threads)

12. Schematic Thread Symbols (External Threads)

13. Simplified Thread Symbols (Internal Threads)

14. Schematic Thread Symbols (Internal Threads)

15. Threads in Section

16. Notes in Threads