Fasteners are wildly used in buildings, automobiles, ships, aircraft, machinery, furniture and other products. Screws that meet ASME or ISO (formerly DIN) specifications comply with these dimensional standards. Match the thread spacing of mating components. Coarse threads are the industry standard; choose these screws if you don’t know the pitch or threads per inch. Fine and extra-fine threads are closely spaced to prevent loosening from vibration; the finer the thread, the better the resistance.