The Stovebolt Site Forums The Shop Area General Truck Talk Bolt thread pitch

Fine threading also has a very shallow pitch (helical angle). This makes vibrations less effective at loosening fasteners over time. Fine thread fasteners are ideal for environments where vibration is considered an issue. Blue loctite helps too.
Another tidbit I learned from engineers, while working for a large heavy equipment manufacturer, is that a bolt needs to be two and a half times longer than its diameter for maximum holding. Typically considered in blind holes. Beyond that doesn’t add much.