1. How to Identify a Bolt

2. The parts of a Bolt H indicates the head G indicates Grade or hardness
L indicates Length
Diameter indicates the Size of the bolt
Pitch indicates thread size
Number of threads per inch on Standard bolts
Distance between threads on a Metric bolt measured in
Millimeters

3. A Scale (or Ruler) is used to determine the dimensions of a bolt.

4. One Side is Inches and the other is Millimeters

5. The 16th Scale is easier than the 32nd Scale for measuring Fractional bolts.

6. Step 1
Determine if the bolt is Metric or Standard

7. Is this metric or standard

8. Is this metric or standard?

9. Step 2 is to determine the Size
Size means the diameter of the bolt across the threads.

10. What is the size of this standard bolt?

11. What is the size of this metric bolt?

12. Step 3 is to determine the thread pitch.
Pitch means the number of threads per inch for a standard bolt.
Pitch means the distance between threads for a metric bolt.

13. Thread pitch is measured with a thread pitch gage

14. What is the pitch of this metric bolt?

15. What is the pitch of this standard bolt?

16. Step 4 is to measure the length
Length is measured from the bottom of the head to the end of the thread

17. What is the length of this standard bolt?

18. What is the length of this metric bolt?

19. The 5th step is to determine the Head size.
Head size is measured from flat to flat.

20. What is the head size of this metric bolt?

21. What is the head size of this standard bolt?

22. If the threads are damaged what tool is used to repair them?

24. Die

25. Die Size Standard Die Size – Pitch Example: 3/8 – 14
Metric Die Size – Pitch
Example: 10 X 1.25

26. Head Size

27. = number of threads per inch
Standard Bolt Sizing
Length
Bolt Size
Head Size
Pitch
= number of threads per inch

28. = distance between threads in mm
Metric Bolt Sizing
8.8
Length
Bolt Size
Head Size
Pitch
= distance between threads in mm