2. Fasteners
Mr. Lombardi

3. Fasteners There are many different types of fasteners.
Screws, Nuts, Bolts, etc.
Each one performs specific task best accomplished by that specific fastener.

4. Screws
A headed threaded fastener that is designed to be used by forming its own threads.

5. Bolts
A bolt is the term used for a headed fastener having external threads that meet an exacting, uniform bolt thread specification

6. Nuts A nut is a type of hardware fastener with a threaded hole.
Along with a bolt, nuts are designed to capture and fasten objects together.

7. Cotter Pin
A metal fastener with two tines that are bent during installation, similar to a staple or rivet

8. Retaining Ring
A small circular steel ring, often resembling the letter "C," that is usually inserted into a slot in a pivot pin to hold the pin in a specified position.

9. Wing Nuts / Thumb Screws
A nut that can be tightened or removed without tools by turning it with fingers

10. Classification There are 7 descriptors for every bolt. Material
Diameter
Pitch/Thread
Head Shape
Finish
Class
Grade

11. Material
Steel
Stainless Steel
Brass
Etc.

12. Diameter T – Thread Diameter R – Root Diameter (minor)
S – Shank Diameter

13. Thread / Pitch
Measured in TPI (threads per inch)

14. Pitch
Thread Pitch is measured with a special gauge

15. Correct Pitch Gauge

16. Incorrect Pitch Gauge

17. Class Class 1 = Loose Class 2 = Free Class 3 = Medium Class 4 = Close
Most are class 2. 3 is for precision assembly, and 4 is used for things like lathe lead screws and measuring instruments.

18. Head Shape
Many, many shapes and sizes

20. Hardware Grade The grade tells the strength of the fastener.
Nuts and Bolts must be the SAME grade.

21. Grades (US) Grade 2 – 74,000psi Grade 5 – 120,000psi

22. Grade 2
Zinc plated low carbon steel. Best for general hardware use where high strength is not required.

23. Grade 5
Made from medium carbon steel, tempered and zinc plated. Best for automotive use and other areas where higher strength is desired.

24. Grade 8
Made from medium carbon alloy steel, tempered, and zinc plated. Best suited for applications where high strength and hardness is required.

25. Grades (Metric)
Grade 8.8
Grade 10.9

26. Grade8.8
Made from medium carbon steel and zinc plated. Best for general hardware use where high strength is not required. Standard metric thread pitches.

27. Grade 10.9
Made from alloy steel quenched, tempered, and zinc plated. Best for automotive use and other areas where high strength is needed.

29. Bolt Identification

30. Metric Bolt Identification

31. Common Nuts
L to R: Wing, hex, hex flange, and flanged weld (for stud welding) nuts.

32. More Common Nuts
L to R: Slotted, square, T, cap (or acorn), nylon locking, and castellated nuts

33. Washers
Four Common Types
Flat
Split
Toothed
Insulating

34. Common Washers

35. Torque To Yield Bolts (TTY)
They are tightened (torqued) until they just begin to stretch
This provides a very consistent clamping load and helps keep an even sealing pressure for the items being fastened

37. Torque to Yield bolts require special procedures
Tighten to the specified torque
Continue to turn the fastener just enough to cause it to begin to stretch
This will be specified in degrees of rotation

38. Torque Angle Gauge

39. Torque to Yield Graph

40. The End