A tool having a flexible shaft, a first end and, a second end and capable of being bent about its axis. The tool transfers rotary motion from a device to tool. The shaft, manufactured from a rigid material, has at least one flexible segment, each flexible segment have at least one sinuous slot ascending in a helical path. With multiple segments, the helical path of the slots can be opposite or the same. With one or more segments having multiple slots, the slots can be parallel or have opposite ascensions, thereby crossing one another. The helical paths can vary within each segment or from segment to segment.
