An arbor bolt holds the blade to the saw rotor and its diameter must match the blade hole size in order to properly secure the blade ( blades commonly use arbor holes and blades favor ). To prevent the saw from loosening the arbor bolt, the threads are reverse-threaded, the rotational spin of the saw blade exerts a tightening pressure on the blade. Development Power miter saws have been available in various forms since the 1970s as specialized cross cut saws but with limited width of cut, especially compared to radial arm saws. Simple miter saws allowed the saw table to pivot allowing miters to be cut in one plane. Compound miter saws also provided saw head tilting allowing compound miters to be cut. Miter saws with abrasive cutting wheels are often used in metal work where they are known as "drop saws" or more commonly "chop saws". Because the blade assembly could only pivot, not translate, these initial designs were limited by blade radius in how wide and deep a board they could cut. However, because their capacities were adequate for handling common sizes of dimensional lumber, and because they were more compact and portable than arm and table saws, chop saws quickly became ubiquitous in construction. Around 1982, the sliding compound miter saw was introduced. This innovation combined all the best features of the compound miter saw with sliding tubes, allowing the cutter head to traverse for a much wider cut. Since then it has become the primary cross cut saw for woodworking, largely supplanting the radial arm saw. Manufacturers warn of possible electrocution when used near water, or other related saws in close proximity. See also Miter box Diamond tools Backsaw Radial arm saw Hack saw Table saw References External links NIOSH Power Tools Sound and Vibrations Database Types of Miter Saw Metalworking cutting tools Metalworking hand tools Saws Woodworking hand tools