Quote:
Originally Posted by Walt White Coupe
Jon, that's not exactly correct. [/url]
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I can only speak from 43 years in aircraft maintenance and have seen what can happen when fasteners have been overtorqued as a result of lubricant being applied to screw threads when not particularly specified by the manufacturer. Worst case I knew of was a helicopter pitch control horn detachment from the rotor blade due to attachment bolt failure. Fortunately this happened on a ground-run but it would have been far worse in flight - subsequent investigation identified the cause to be inappropriate use of lubricant on screw threads. Unless a maintenance instruction specifies a 'wet' torque figure, it must be assumed that the parts are assembled in a 'dry' condition.
Certainly your article is correct in stating that lubricant must not be applied to hardware seats (faying surfaces) as this will allow increased slippage, thereby amplifying torque, but you can also think of the entire engagement area of a male and female screw thread as being a continuous 'faying surface' - thread friction will be reduced by a factor of around 25% and the applied torque will be increased accordingly.