By Bill Washington

When answering this question, it is important to understand what happens when we tighten a bolt.  The bolt acts as a heavy spring that clamps two or more pieces together. When we turn a nut we stretch the bolt.  Stretch or elongation provides clamping force. Not enough clamping force allows the nut to vibrate loose causing leaks. Too much clamping force causes gasket damage, bolt galling, ...