Posted by Jack Cain on Friday, January 04, 2002 at 10:04PM :
In Reply to: Re: You're right about Oiling and Greasing posted by Cheyenne Dave on Friday, January 04, 2002 at 8:25PM :
Torque which is the resistance to a twisting force is not the same as clamping load and indeed the two are not directly proportional.
Given the same torque value for two different sizes of bolts will yield different clamping forces - sometimes significantly so.
A torque value of 110flb on a 5/8 bolt can easily achieve 10,000 lbs of clamping load.
If lubed with 30 wt oil the necessary torque to acheive the same clamping load is only 85flb. Depending upon the friction reducing ability of the lubricant being used it is possible to achieve this level of clamping load with even lower levels of torque.
This is why some torque charts give a dry and wet ( 30wt oil using being the reference standard for wet ) value for the recommended torque setting. Most modern repair manuals however only give a torque value and assume that you already know that it is the dry value.