# NJATC Torque

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1. How is the grade of a bolt determined? WB9

An SAE bolt thread size is determined by measuring what? WB9
By adding the number 2 to the number of hash marks on the bolt head

2. An ISO bolt thread size is determined by measuring what? WB10
mm form crest to crest
3. the length of a bolt is determined by measuring what? WB10
The length of the shaft
4. The formula for torque is what? WB1
Torque = length x force
5. The fastening process is comprised of four distinct phases. WB7
• Run Down
• Alignment
• Elastic
• Plastic (yield)
6. The total force required in a torque application is comprised of two distinct regions. What are they? WB6

Defined how?
• Static breakaway torque
• Dynamic applied torque

• Static breakaway torque: the friction the fastener must overcome
• Dynamic applied torque: the torque required to move or rotate the fastener after it has been seated
7. What is the 90/10 rule regarding friction? PP7
90% of torque is friction and 10% is stretch
8. The direction of the torque can be determined by using the right hand grip rule: ……which is?
if the fingers of the right hand are curled from the direction of the lever arm to the direction of the force, then the thumb points in the direction of the torque.[6]
9. Some estimate that adding a lubricant could reduce the required torque reading by up to? What %
40 percent
10. even though you can’t see it, a tightened bolt has been stretched a microscopic amount, and this stretch is called Tension.

Just like a stretched spring, which tends to pull back into its original shape, a stretched bolt tries to pull itself back to its normal state. It’s this pulling back force, called the “_______” that actually maintains the tightness of the joint.
clamp force

Note: But lubrication on the bolt threads—and a whole host of other factors—can cause fluctuation in torque readings. So once you add a lubricant of any kind to the threads, all bets are off as to whether the same torque setting will truly secure the bolt. That’s because nobody really knows how the lubricant affects the torque measurement on a bolt without performing a scientific study using expensive lab instruments.
11. Describe the benefits of a smart bolt.
A smart bolt allows you to not worry about the tension being used for torque and especially when lubrication and stainless steel are involved.
12. Is a stainless torque value different than a non-stainless torque value?
yes.  Usually 2-3 lbs difference.
13. Can you use a lubricant with a stainless fastener and should you for torque value?
No.  Because this can change the torque reading by as much as 40%
 Author: johnbowens ID: 55501 Card Set: NJATC Torque Updated: 2017-12-06 18:37:38 Tags: torque Folders: Description: torque Show Answers: