Screws . Screws provide more strength and holding power than nails. Additionally, if something needs to be disassembled, screws can easily be removed. Like nails, screws are available with different coatings to deter rust. They are manufactured with four basic heads and different kinds of slots. by HowStuffWorks .com Contributors. Next. Like nails, screws are (usually) small pieces of hardware used to hold materials together. One of the main differences is that screws are designed to be able to be removed and replaced easily without damage to the screw itself or the material it connects. The inserts are shaped to minimize stress, and they expand as the screw enters. Self-heree in all sizes and tip types, and they have various shaped heads. When you choose the right size self-tapping screw, you should take into account the length …

Whether a bolt, nut or screw, you know the fastener that will work to make the repair secure. But for those just putting on the DIY hat, there are a few hints that can help when choosing from a wall of nuts and bolts in a hardware store. How Screw-Drive Vehicles Work. It was also a notoriously ravenous consumer of fuel. On the up side, it could reportedly haul (again, on snow) 20 tons (18,144 kilograms) of cargo, such as logs, by towing it on one or more sleds. Screw drives tend to work well on heavy snow, in mud, even on ice or marshland. 10 Medieval Torture Devices. A wooden bar slid down along the metal bars, pressing the thumbs against the bottom. A screw pressed the wood bar downward, crushing the thumbs painfully. The thumbscrews were an elaboration of an earlier device known as the pilliwinks, which could crush all 10 fingers and resembled a nutcracker [source: Parry ].

Twin-screw supercharger. A twin-screw supercharger operates by pulling air through a pair of meshing lobes that resemble a set of worm gears. Like the Roots supercharger, the air inside a twin-screw supercharger is trapped in pockets created by the rotor lobes. But a twin-herepresses the air inside the rotor housing. Mar 16, 2011 How Screw-Drive Vehicles Work. But among the first-published designs for a screw-drive vehicle was that of Jacob Morath, a Swiss immigrant to the United States who patented a twin-screw ploughing machine in 1899. Perhaps one of the most highly exposed of these not-so-well-known screw-propelled machines was the Armstead Snow Machine,. For instance, an electric screwdriver has a very large gear reduction because it needs lots of torque to turn screws, but the motor only produces a small amount of torque at a high speed. With a gear reduction, the output speed can be reduced while the torque is increased.