Difference between a snug tight and a fully tensioned bolt?

[chris_usyd]

anyone knows the difference between a snug tight and a fully tensioned bolt?
thanks in advance:thumbs:

 

[Simon Bridge]

Turn the bolt until it stops, there is little or no visible gap and does not rattle when you shake it - a low-to-nil setting on a torque wrench for eg or just "finger tight". This is "snug tight".

The bolt will turn further than that - when it is turned to a non-zero setting on the torque wrench, it is a tensioned bolt. When it is tensioned to the enginerring spec, then it is "fully tensioned". Above or below the spec then it is over or under tensioned respectively.

http://www.skf.com/files/880426.pdf

 

[chris_usyd]

Turn the bolt until it stops, there is little or no visible gap and does not rattle when you shake it - a low-to-nil setting on a torque wrench for eg or just "finger tight". This is "snug tight".

The bolt will turn further than that - when it is turned to a non-zero setting on the torque wrench, it is a tensioned bolt. When it is tensioned to the enginerring spec, then it is "fully tensioned". Above or below the spec then it is over or under tensioned respectively.

http://www.skf.com/files/880426.pdf

thanks very much, simon.
it helps.

 

[afreiden]

The more you pretension a bolt, assuming you are doing it correcting (e.x. using washers), the better that bolt can resist fatigue due to cyclic or repeated loading. So, there are sometimes fundamental reasons for pretensioning bolts to a certain spec, aside from making sure the bolt doesn't come loose..

 

[Simon Bridge]

So, there are sometimes fundamental reasons for pretensioning bolts to a certain spec, aside from making sure the bolt doesn't come loose..

... which is the most likely way someone may be puzzled about this :)
... and the link in post #2, reappearing in #3, goes into detail - yep.

And people think that "doing up bolts" is simple ;)