Clamping Force non-joint

[gordohongo112]

i was wondering how i would determine a bolts clamping force, or the amount of tension in the threads when the bolt is screwed into a flange. there is no washer or nut. the bolt is directly screwed into the part.

 

[CoryPad]

Is there anything between the bolt head and the flange? If so, you have a joint - one with a tapped hole, which is very common.

If you don't have anything clamped between the bolt head and the flange, then you have the equivalent of a threaded plug. This can develop tension in the threads, or very commonly, shearing of either the bolt threads or the flange threads.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[gordohongo112]

no there isn't anything between the bolt and flange.

yes this is a threaded plug. would i just use the normal T=KDP formula to dermtine the clamping force/tensile force?

 

[MintJulep]

Is this the same, or different than your gland thread?

 

[CoryPad]

It depends on the joint geometry. Is there a significant unengaged shank length? Almost assuredly not. If you have a short screw going into a tapped hole, then this configuration has nonuniform force distribution throughout. This isn't suited to easy calculation. Plus, this type of joint is notorious for large torque/tension variation during assembly due to the unfavorable bolt to joint stiffness ratio and the small rotation angles involved.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[gordohongo112]

yes it is.