Quiz/Answers

1. Bolts are graded and marked for identification. Are nuts also marked and graded?
2. What does a single notch on each hex corner of a nut mean?
3. You have a bolt with stripped threads. Why? Name at least 3 reasons other than the bolt quality.
4. If a Grade 5 bolt was torqued the same as a Grade 2 bolt, will it have the same or greater clamping force than produced by the Grade 2?
5. You have a shear problem. How many ways can it be solved?
6. Will a lubricated bolt tend to loosen more from vibration?
7. How many times can you safely reuse a nut?
8. Approximately how much clamp load is lost from joint compression during the first 90 seconds after initial tightening?
9. Is there a ‘wrong’ way to use a flat washer?
10. The approximate clamp load of a ½-13 Grade 8 fastener, 21/2 inches in length, is 12,770 pounds when torqued to 75% of its proof load. The joint thickness is 2”. The joint relaxes 0.002”. How much clamp load is lost?

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