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 ...

It’s easy to cut bolts and small machine screws to length. On the other hand, there isn’t any job so small or simple that it can’t be done wrong, and this is a classic example. Get it right, and you ...

Jam Handy! Provides a detailed overview of the process of cutting screw threads on a lathe. It explains the different types of screw threads, the importance of precision in machining, and outlines the ...

Roy Underhill shows how to use an 1889 foot-driven metal working lathe. Make your own darn metal screws with this 1889 foot-powered lathe! Roy shows how to cut perfect threads, cones and tapers in ...

The basic tapping screws are classified as thread forming and thread cutting. Thread-forming tapping screws displace the material adjacent to the pilot hole so it flows around the screw threads.

Scientific American is part of Springer Nature, which owns or has commercial relations with thousands of scientific publications (many of them can be found at www ...

Twist drills do not make accurately sized or good finish holes; a reamer of some type is often used to cut the final size and finish. A reamer will not make the original hole; it will only enlarge a ...

Self-tapping screws are usually drilled into pre-made holes (pilot holes) in metals, such as zinc, aluminum, and bronze and its alloys, as well as plastics and resin-impregnated plywood. They create ...

One of the six simple machines, a screw is nothing more than an inclined plane wrapped around a center pole. While today screws come in standard sizes, and typically are tightened by turning clockwise ...