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Bolt Pre-tension

Bolt Pre-tension

Bolt Pre-tension

(OP)
Hi All:

I am torqueing the nut so that assembly does'nt come out, I knoow the pre torque but I do not know how much this torque will create pre tension on nut and bolt.

So could anyone tell me the basic relation between torque and tension in a bolt.

Well I used T=FKD where F is the tensile force
T=torque, D is the nominal dia of bolt/nut, K is torque coefcient.

Thanks

RE: Bolt Pre-tension

Hi harrai

Depends on how accurate you want the pre-load.
If your using a wrench then the pre-load will be subject to
+/- 20% or thereabouts.
The formula you have used is very approximate.
have a look at this site also:-

http://www.roymech.co.uk/Useful_Tables/Screws/Preloading.html

Regards

desertfox

RE: Bolt Pre-tension

i think we're going off on a tangent.  the OP has asked only to hold the pieces together, not to design them to withstand a specific tension load (which they may well do, but like most things here, this'll unfold with further posts !)


try goggling or yahooing "bolt intsallation torque design guideline" ... i got this reference for you ...
http://www.shurjoint.com/pdf/B-17%20Bolt%20torque.pdf

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