Advice on nuts and bolts

Q: Can you tell me how to tell if a nut or bolt is usable or not.  I think I over-torqued a bolt/acorn nut combination due to using a cheap torque wrench which didn’t click. Note to self: cheap tools cause more problems than they solve.

Tommy G, USA

 A: It has often occurred to me that I ought to check how accurate my torque wrenches are, rather than just trusting that they will be okay, as I have occasionally felt that fasteners seem rather tighter that I would have done them without the wrenches. Unfortunately, I have never quite got round to actually doing it so you have spurred me on. For now though, a visual check to assess distortion of thread forms, perhaps using a thread pitch gauge, should suffice –provided the components are not critical such as big end bolts.