A polygon machining method whereby first polygon machining using a polygon cutter is carried out on a workpiece, followed by machining using tools other than the polygon cutter, then second polygon machining using the polygon cutter again. The polygon machining method comprises: a first polygon machining step in which a main axis and a tool main axis are synchronously rotated such that the rotation speed of the main axis and the tool main axis are at a ratio required for the first polygon machining, and polygon machining is carried out; a machining step in which the ratio is changed to a second synchronization ratio such that the main axis rotates at a rotation speed required for machining after the first polygon machining, the main axis and the tool main axis are synchronously rotated, and machining is carried out on the workpiece that has received the first polygon machining; and a second polygon machining step in which the main axis and the tool main axis are synchronously rotated such that the rotation speed of the main axis and the tool main axis are at a ratio required for the second polygon machining, and polygon machining is carried out.

A high-speed precision interrupted ultrasonic vibration cutting method includes steps of: (1) installing an ultrasonic vibration apparatus on a machine tool, and stimulating a cutting tool to generate a transverse vibration, so as to realize varieties of machining processes; (2) realizing an interrupted cutting process by setting cutting parameters and vibration parameters to satisfy an interrupted cutting conditions; and (3) turning on the ultrasonic vibration apparatus and the machine tool, and starting a high-speed precision interrupted ultrasonic vibration cutting process. High-speed precision interrupted ultrasonic vibration cutting is able to be realized through the above steps during machining of difficult-to-machine materials in aviation and aerospace fields. A cutting speed is enhanced significantly, and exceeds a critical cutting speed of a conventional ultrasonic vibration cutting method and an elliptical ultrasonic vibration cutting method and even a high speed range of a traditional cutting method.

A hole saw including a plurality of sidewall openings is provided. The sidewall openings are shaped and grouped in patterns that improve debris ejection of the hole saw and that allow for easy access to the interior of the hole saw for manual debris removal by the user. The opening groups are space from each other by larger uninterrupted areas such that the hole saw has a high strength despite the number and size of openings provided in the saw sidewall.

A hole saw including a plurality of sidewall openings is provided. The sidewall openings are shaped and grouped in patterns that improve debris ejection of the hole saw and that allow for easy access to the interior of the hole saw for manual debris removal by the user. The opening groups are spaced from each other by larger uninterrupted areas such that the hole saw has a high strength despite the number and size of openings provided in the saw sidewall.