A method for drilling through an assembly forming a stack of at least two different materials uses a drill bit having at least a first cutting edge and a second cutting edge inclined in an axial plane of the drill bit so that the end of the drill bit has a projecting conical shape. The first cutting edge is configured to drill a first material. The second cutting edge is made differently from the first cutting edge, to drill a second material. A first rotational drive axis of the drill bit is laterally offset during the drilling by an offset distance D relative to the axis of the drill bit in a direction opposite the first cutting edge when the drill bit is drilling through the first material, and alternately, in a direction opposite the second cutting edge when the drill bit is drilling through the second material.

A double eccentric positioning apparatus uses two equal offset eccentric bushings to accurately position a tool (such as a drill bushing) in two dimensions. Miniature servo motors and precise gearing control the rotation of each eccentric bushing, which controls the direction of the offset vectors. The offset vectors are used to determine the final position of the drill bushing. The desired rotation angles can be mathematically calculated based on desired position. The inner eccentric bushing is located concentric to the offset of the outer eccentric bushing. This allows any position, within a radius of two times the eccentric offset, to be achieved. The use of worm gearing on the eccentric bushings prevents back-driving of the servo motors, due to the lead angle of the worm gears, and the friction between the worm wheel and worm gear.

A double eccentric positioning apparatus uses two equal offset eccentric bushings to accurately position a tool in two dimensions. Miniature servo motors and precise gearing control the rotation of each eccentric bushing, which controls the direction of the offset vectors. The offset vectors are used to determine the final position of the drill bushing. The desired rotation angles can be mathematically calculated based on desired position. The inner eccentric bushing is located concentric to the offset of the outer eccentric bushing. This allows any position, within a radius of two times the eccentric offset, to be achieved. The use of worm gearing on the eccentric bushings prevents back-driving of the servo motors, due to the lead angle of the worm gears, and the friction between the worm wheel and worm gear.

A tool that cuts a hole for a single or double electric gang switch box. By having four blades, all cutting at the same time and in the shape of the switch box, a more accurate and appropriately placed hole may be provided. The hole saw may be configured with two centering drills so the tool is guided into the cut. An eccentric drive mechanism converts a rotary drive into reciprocating movement of perpendicularly opposed pairs of blades to cut a rectangular opening.

Provided are a control device and a computing device capable of adjusting synthetic vibration for a machine tool. This control device, which controls a machine tool, comprises: a vibration command generation unit that generates a vibration command for vibrating an implement of the machine tool or a workpiece; a relative vibration command generation unit that generates a relative vibration command for vibrating the implement and the workpiece relatively; and a vibration phase adjustment unit that adjusts the vibration phase of at least one of the vibration command and the relative vibration command on the basis of the vibration command and the relative vibration command.

Provided are a control device and a computing device capable of adjusting synthetic vibration for a machine tool. This control device, which controls a machine tool, comprises: a vibration command generation unit that generates a vibration command for vibrating an implement of the machine tool or a workpiece; a relative vibration command generation unit that generates a relative vibration command for vibrating the implement and the workpiece relatively; and a vibration phase adjustment unit that adjusts the vibration phase of at least one of the vibration command and the relative vibration command on the basis of the vibration command and the relative vibration command.