If you read the previous posts, sometimes a lot of torque was needed to achieve the 1.5 threads showing, not all nuts are equal in size, nor are bolts, have a bolt a fraction to short and a nut a fraction to deep and you struggle... you erm, don't just throw any nut and bolt in there and hope for the best.
I still remember the Westland Split pin holes, that must have been drilled from both sides or offset as they would line up one side, but not the other.