Calulating Torque on a nut
Calulating Torque on a nut
(OP)
I am designing a pnuematic clamp device to hold a nut while a bolt is threaded through a plate and into the nut. How do I calculate the torque on the nut to properly design the clamp mechanism. I am using a M10 X 1.0 bolt and nut.





RE: Calulating Torque on a nut
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Calulating Torque on a nut
Ted
RE: Calulating Torque on a nut
RE: Calulating Torque on a nut
Have a look at this site it will show you how to calculate the clamping force from the torque:-
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Failing that for a rough estimate of the clamping force use this formula:-
F= 0.2*T/(d)
where F=clamping force
T= Torque
d= bolt dia
0.2 = friction factor (dry)
desertfox
RE: Calulating Torque on a nut
In my reference book, supposedly as used by Airbus manufacturing, (ISBN 3-8085-1910-X), M10 x 1.0 can have a torque value ranging from 36Nm to 51Nm, depending on the friction, i.e. they quote µ from 0.08 to 0.14 If you then consider bolt grades, the range goes from 36Nm to 88Nm, the 36Nm value being applicable to 0.08µ with a bolt Grade 8.8 and the 88Nm value applying to 0.14µ with a bolt Grade 12.9
It seems so easy to pull the head off a bolt by simply having it lubricated, if the torque value recommended was for an unlubricated condition. It's always a dilemma for me when quoting a recommended torque, as I try to cater for the operator not having the correct lubrication. It's pretty difficult to cover every eventuality, while still ensuring the joint is as secure as it was intended in it's design.
RE: Calulating Torque on a nut
RE: Calulating Torque on a nut
If you want to feel 20% better, plan on the clamp resisting 120% of the applied torque or 84Nm.
How do you propose to prevent cross-threading when the bolt contacts the nut?
Are you wanting to calculate the clamp force necessary to cause enough friction force resistance under the nut to resist rotation of the nut? Use 1/2 the average diameter of the nut face for the radius through which the friction force acts. Use the clamp force x a friction factor to calculate the friction force. The friction factor will depend on lubrication or dry friction conditions under the nut. Friction force x 1/2 average diameter = torque resistance.
Ted
RE: Calulating Torque on a nut
http://www.riverhawk.com/boltloading.php
RE: Calulating Torque on a nut
RE: Calulating Torque on a nut
Ted