Abrasive cutting tools are any number of tools which cut by rubbing a hard material quickly over the object to be cut. One of the most basic types is a grinding wheel. An abrasive material is hard and rough, and wears down whatever it is rubbed against. These tools are embedded with an abrasive material.
Because abrasive cutting is efficient and relatively inexpensive, abrasive cutting tools come in a great variety. If you look hard enough, you're likely to find them for just about any type of cutting job you might have. For any solid that needs to be cut, a tool exists for the job.
The abrasives in abrasive cutting tools are usually very hard crystals. In order to work well, these tools must use an abrasive that is harder than the material to be cut. Because diamond is the hardest substance on earth, it is used when it's necessary to cut or polish very hard substances.
Other abrasives include aluminum oxide, called corundum in its crystal form; garnet; and emery. Abrasive cutting tools use the friction of these abrasives to cut materials ranging from wood and metal to stone and gems. The softer tools, an iron file for example, are used to cut softer materials like wood. Harder materials such as gems require those with very hard abrasives, like diamond.
Abrasive cutting tools can range from the very simple to the very complex. A very simple one is a metal file. The rough surface of the file can be used to cut or rasp wood or soft metals, but it requires a lot of physical work. Adding power to tools gives us the slightly more complicated cutting or grinding wheels. These are often used to cut and polish stone, and work much faster than hand tools.
When we come to the more complex abrasive cutting tools, we run into things like abrasive water jet cutters. These tools are often computer programmed to cut complex shapes from metal sheets in manufacturing. They operate by shooting a high-powered stream of water at the metal. Inside the water are abrasive crystals, such as garnet, and the pressure of these abrasives can cut metal with incredible accuracy and speed. From the most simple roughened piece of metal to the most complex and accurate computer-driven machine, these devices find their place in almost every situation in which something hard needs to be cut.