Answer is:
Hexagonal nut
Explanation:
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![Which nut is used for structural and machine tool construction?](https://mcqfinder.in/uploads/images/objective-questions/mechanic-diesel-set-1-fastening-and-fitting/mechanic-diesel-set-1-fastening-and-fitting-id-1-e.jpg)
Answer is:
Castle nut
![Which type of nut required to align the axle shaft hole and slot of the nut for locking?](https://mcqfinder.in/uploads/images/objective-questions/mechanic-diesel-set-1-fastening-and-fitting/mechanic-diesel-set-1-fastening-and-fitting-id-2-e.jpg)
Answer is: