Decking screws have rough threads and an even leading shank, similar to Wooden screws. They're also meant to withstand rust and corrosion, which is an additional feature in frequent with wood screws. equation, it can be found the screw is self-locking if the coefficient of friction is greater in comparison https://typesofgeodesicdome71370.ampedpages.com/a-review-of-lead-screw-examples-56675140