From Fastener World Magazine, May/June 2014, Volume 146
As handheld electronic devices have gotten smaller and lighter, the fasteners that hold them together have had to follow suit. Although miniature metric and imperial machine screws have been used in eyewear, watches, and cameras for many years, it is only relatively recently that very small variants of thread forming screws have become commonplace. It is impossible to explain why this is the case, but probably stems from the fact that thread forming in plastics and light metals is a practice that has itself only recently gained universal acceptance.