They hold together everything from the most delicate watch to the largest bridge. The world is literally kept from coming apart by screws and bolts, and yet we don’t often give a thought to these ...

Attaching metal pieces to one another with a screw is relatively straightforward. But using threaded fasteners on plastics, which are lightweight, low-density materials compared to metals, can be ...

The strength of some internal threads is more sensitive to tap diameter than previously thought. • Cold-formed threads are no stronger than cut threads when holes are correctly sized. • Cut threads ...