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"I have told you many times. If you twist the screws, you must twist them three times and half times. Because if you twist them too hard and die, the screws will easily break." Master Zhang said.
Just this, Sun Erhu couldn't understand the truth. Isn't it right to tighten it? Why would it be easy to break. If this is the case, isn't it okay to twist it twice and a half rounds? Why do you have to twist it to three times and then back half round? Isn't it useless to do more work?
Sun Erhu looked at Master Zhang, not only did he not understand, but a bunch of question marks appeared on his head.
Master Zhang, repeating it again and again, and then saying one more thing is: "This is what people do abroad, which is the international standard and the highest international standard. It is absolutely right to do so."
Even Old Wei couldn't listen to this and complained: "The foreigner said that the moon is sweet, but you said it is sweet. If the moon belongs to Zhu Bajie, you said that the moon belongs to Zhu Bajie."
"Old Wei, you--" Master Zhang was so anxious that helmet on his head, "Others' production abroad is our advanced, and we should learn from others humbly."
"Why do you have to tell me a truth from others? Mr. Min?" Lao Wei asked Mr. Min, who has a good level of education.
Director Min looked at Teacher Ning.
Ning Yunxi thought, "Master Zhang said, it may be that the screw will be in elastic deformation after being tightened, especially under high temperature and vibration load conditions, which will cause creep. After the screw becomes plastic deformation, the strength will drop significantly or even fail. Retreat half a circle, the purpose is to restore the elastic deformation, eliminate pre-tightening stress, and make the life of the screw longer. This is an effect that cannot be achieved by twisting two and a half turns. Simply put, it can be described as warm-up before exercising the screw."
Speaking of exercise, Sun Erhu, who had attended physical education class in the school, understood and said: "It's like stretching his legs before exercise. The teacher said that it is to prevent injuries during exercise."
"It's almost the same principle." Teacher Ning nodded, "Of course, the specific theoretical knowledge used is definitely not the same. Like a screw, when it tightens, it follows a principle of 541 rule. The torque of the clamping force only accounts for 10%, 50% is the friction force against the screw head, and 40% is the friction force against the thread."
Old Wei, who was standing outside and stretched his neck to listen to Teacher Ning's words, was hit on his shoulder. He turned around and found that when it started, a bunch of workers all ran over to listen to the class.
The people surrounded Teacher Ning in the middle layer by layer.
Old Wei asked Master Zhang: "Do you understand?"
Master Zhang read a lot of books and should be able to understand it. But in fact, Master Zhang was a little confused and said honestly: "It seems that I have talked about this in the book I have turned on, but I don't understand it very well after reading it."
Chapter completed!