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 ...

Wood fastening is at the heart of all woodworking and construction work. Much of this functionality is due to the design of ...

This close-up of the ball contact in a profile projector shows a gothic arch. It consists of at least two radii slightly larger than the ball used, but offset so the raceway touches the ball on both ...