The hook should be scrapped when one of the following occurs:
② Dangerous section wear up to 10% of the original size;
The ③ aperture is 15% higher than the original size.
④ Hook body Twist deformation more than 10 °;
⑤ Hook Dangerous section or hook neck to produce plastic deformation;
⑥ hook thread is corroded;
The bushing should be replaced when the ⑦-hook bushing wears up to 50% of the original size.
⑧ piece Hook mandrel wear up to the original size of 5%, should replace the mandrel.