So, a bolt you tightened down completely failed and broke into two pieces. Why did it happen? Did you tighten it and use a torque wrench to insure the proper tightness?
The first things you need to determine include what size bolt, how many threads per inch and what grade of bolt. The grade of bolt is marked on the head of the bolt. The chart shown is for Grade, 2, 5 or 8.
Why did this bolt fail?
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