Torque of nuts and bolts, which one should you use?

sonflowerinwales

sonflowerinwales

In the country
Good afternoon Covers
I was presented with the problem of some connector screws not being secured to the correct torque value. We have re-checked the current build and around 25% have tightened up a little.
This led me to question the technique used, for which no-one could give me a straight answer....
So, todays question:- which do you tighten, the nut or the bolt?
i.e. Hold the bolt still, torque wrench on the nut or vice versa?
Cheers
Paul
 
V

Vthouta

That's really a good question. Even I would like to know the answer. But, we use the digital torque tester to verify the torque specification has been implemented correctly.
 
Miner

Miner

Forum Moderator
Leader
Admin
Provided the bolt does not encounter friction from the hole or other material such as gasketing, the should be no difference between the two approaches. However, significant friction on the bolt could result in torque losses to overcome that friction that would not appear on the nut.
 
A

AndyN

Moved On
sonflowerinwales said:
Good afternoon Covers
I was presented with the problem of some connector screws not being secured to the correct torque value. We have re-checked the current build and around 25% have tightened up a little.
This led me to question the technique used, for which no-one could give me a straight answer....
So, todays question:- which do you tighten, the nut or the bolt?
i.e. Hold the bolt still, torque wrench on the nut or vice versa?
Cheers
Paul
Click to expand...

Paul - It's somewhat dependent on the application and type of fastener, any locking devices, washers etc. As a VERY general rule, nuts are tightened onto bolts, machine screws, studs etc.
 
S

Sean Kelley

I agree with Miner and Andy that it should not matter which one you are on for checking the torque rating. In reality you likely get better values from the nut and normally you tighten and loosen the nut not the bolt. There are obviously some exceptions when space or other reason will not allow access to the nut.
 
sonflowerinwales

sonflowerinwales

In the country
Hi everyone and thanks for your replies.
I agree, common sense says to tighten the nut as there is additional friction for the bolt head.
Next question is does anyone have data to support this.......?
Thanks
Paul
 
sonflowerinwales

sonflowerinwales

In the country
Thank you everyone.
After a little reading this morning, we have to see which is the side of the joint which offers least resistance and torque from that side.
When we get some results I'll share.
Enjoy your day.
Paul
 
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