The hook should be scrapped when one of the following conditions occurs:
② Dangerous section wear up to 10% of the original size;
③ aperture increased by 10% compared to the original size;
④ Hook body Twist deformation more than 10 °;
⑤ Hook Dangerous section or hook neck produces plastic deformation;
⑥ hook thread is corroded;
⑦ Chip Hook bushing wear up to 50% of the original size, the bushing should be replaced; ⑧ Plate Hook mandrel wear up to 5% of the original size, the spindle should be replaced.