Alvord Polk 650-H High-Speed Steel Construction Reamer, Left Hand Spiral Flute, Round Shank, Uncoated Finish, Size: 9/16 Inch Left-hand spiral reamers are good for use in through holes (holes that extend all the way through a workpiece), as they push chips ahead of the tool and into the hole Spiral reamers are recommended for reaming holes with interruptions, as they prevent damage to the workpiece edge and tool Round shank tools are cylindrical and should be held in a good-quality toolholder in order to prevent the reamer from slipping in high torque applications, which can cause tool freeze, loss of accuracy, and tool damage Uncoated (bright) tools have no finish or coating. They are a good choice for general purpose applications High-speed steel is a common general purpose steel for cutting tools, is compatible with a variety of materials, and tends to be lower in price than cobalt steel or carbide