bolts/nuts

[DCMV]

Is there any asme code that specifies which way the nut has to be on a bolt, is there such thing as a backword/upside down nut? I know the material/grade should be showing when checking a bolt up connection. I'm just wondering if 1 nut out of 45 is backword (not showing 2H) is this good reason to reject bolt up?

 

[rodofgod]

Nuts typically have a bearing surface as do bolts. That should be the point of contact or interference. It depends on the application as to weather a nut on the wrong way would warrant rejection of an entire part of the job. But I have seen it do so before.

 

[Duwe6]

I can't recall where I read it, but it was from a source I considered reliable: The bearing capacity of a 2H nut is unchanged from the 'washer face' to the '2H' side. Only if calibrated torque is being used to install the nuts, AND the nut is the turned member AND the calibrated torque is very close to the minimum allowable torque of that lot of bolts to achieve the minimum pretension, does it become a problem.

It is just a 'workmanlike appearance' item, like facing all the bolts the same way and using all the same length bolts in any given connection. And nobody can see it from the ground, nor after the painters roll on the usual 10-30 mils of goopy touch-up paint. IOW, these items only get rejected if the Inspector is 'green' or is having a bad day; or most likely is upset about the lackadaisical attitude and inattention-to-workmanship items of the bolt-up crew(s).

. . . Got The Tee-shirt [both a 'green' one and a "lackadaisical" one.

 

[rodofgod]

Wow! that's a pretty different attitude,I am surprised! Shouldn't the 'nut' always be the turned member? Unless, of course it becomes a captive 'nut'? I know we measure the torque from 'nut' side only? I would have thought that it was good engineering practise to set up and maintain a bolting regime that conformed at least to best practise and standard minimums!