What is Screw?
:''Screw can also be a [[slang]] word for [[sexual intercourse]].'' [[File:Screws.jpg|thumb|220px|A collection of screws]] [[File:Aula_torcao.JPG|thumb|220px|How to use a screwdriver]] A '''screw''' is a sharp piece of threaded [[metal]] similar to a [[nail]]. Unlike a nail, a screw has [[spiral]] [[groove]]s down its spike. A screw is pressed down against [[wood]] and turned with a [[screwdriver]]. Turning the screw to the right makes it go into the wood. The grooves cut into the wood. This prevents the screw from falling out, as a nail might. Turning the screw to the left pulls it out of the wood. Screws can be made of [[steel]], [[iron]], [[brass]], [[bronze]], [[plastic]], etc. There are also machine screws and self-tapping screws. Machine screws are [[bolts]] which have [[screw thread]]s. The threads matched with [[nut (hardware)|nuts]] with female threads. Screw threads are measured either in millimeters or in numbers. They are used in furniture, doors, appliances, etc. == Screwing and screws == Screwing is the neatest way of holding together two materials. If no glue is involved, then the screwing can be dismantled. These are three different types of screw. #Countersunk: First you drill a pilot hole into the wood. Then you can widen out the top by using a countersink drill bit. The head is flat on the top. #Raised head: Has a slightly domed head, raised above the surface. #Round head: Domed head above surface, broader than underneath. Do not place screws in line as this weakens the wood. Use the right size screwdriver for the screw head. A screwdriver that is too slim can damage the slot, too wide can tear the materials.<ref>{{Cite web |url=http://www3.telus.net/findNchoose/StrippedWoodScrews.html |title=How to Repair Stripped Wood and Metal Screw Holes |access-date=2009-06-24 |archive-date=2009-08-19 |archive-url=https://web.archive.org/web/20090819030907/http://www3.telus.net/findNchoose/StrippedWoodScrews.html |url-status=dead }}</ref> Screw threads in both wood and metal can become stripp