Originally Posted by thescreensavers
Adding anything to the threads WILL change the K value (Wrench Torque = K *Axial Force*bolt dia )
Most anti size manufactures will list K values for their anti-seize. You may email permatex for an answer but I found these with a quick google.
Quote
In the case of Permatex products the K factors are -
* Standard Anti-Seize K = 0.18
* Copper Anti-Seize K = 0.16
* Nickel Anti-Seize K = 0.13
If Normal Dry threads are 0.2, and std AS is .18,
So for example using 15 ft/lb or 180 inch-lb with M14 thread
180 in-lb = .2 * F * .551(M14)
Solving for F (Axial force or clamp force)
Dry Threads Axial Force (Clamp Load) = 1633.4 lbs
Standard Anti-Seize = Axial Force (Clamp Load) = 1814.9
Nickel Anti-Seize K= Axial Force (Clamp Load) = 2512.9
11% Increase in clamp load(std AS), for the same equivalent dry torque you can lower your wrench to 162 in-lb or 13.5 ft/lb when using Anti-seize.
Nickle though that's a whopping 54% increase in clamp load, you would want to lower your torque values accordingly. To 117 in-lb or 10ft/lb
In reality, YMMV as K value is different with every bolt, anti-seize or lubricant does even that variation out but, when you add the friction of the head into the calculation, your preload/clamp force can actually vary more than 11% with a torque wrench(±25-30%) so that is likely why permatex says to use normal torque spec, as it is within error.
From the Permatex web site TDS for their anti seize product. I think they may know a thing or two about anti seize compounds:
5. Apply Anti Seize to the parts that require protection.
6. Reassemble parts using normal torque values.
