Abstract: A power tool comprises a base unit and a motor unit. The base unit includes a handle and a first electrical connector. The motor unit includes an electric motor and a second electrical connector. The motor unit is configured to be releasably connected to the base unit. An electrical connection is established between the first electrical connector and the second electrical connector when the motor unit is properly connected to the base unit. A sensor is configured to determine whether the motor unit is properly connected to the base unit.

Abstract: A pair of centering spindles are disposed away from cutting spindles and movably in the direction of Z or parallel with the axial center line of cutting spindles. A plurality of log center detecting means are disposed along the Z direction in relative to a log chucked by the centering spindles. A pair of holding members are mounted movably in the directions of X, Z, and Y including components orthogonally intersecting the X and Z. By way of controlling means, the centering spindle holding a log is caused to rotate at least one revolution thereby enabling the log center detecting means to determine each position of axial center which is assumed to constitute the axial centers at both end faces of the log, the virtual line passing through every positions of axial centers in Z direction is aligned with the Y, and the holding members are moved in the Z direction to hold the log, after which the chucking of log by the centering spindles are released.

Abstract: A method is disclosed for producing signs having raised, prismatic graphic images such as letters, numbers and other graphic images. Initial values for the graphic images are provided, and includes information defining an initial graphic representation for the graphic images, and may also include a return, which is the measure of distance by which the graphic images are raised relative to a background of a sign. A cutting tool is provided and has a radius and a cutting angle. One tool path is determined using the initial graphic representation. Tool passes and depths for the other passes are determined using the initial graphic representation, the cutting angle, and a distance which is not greater than the tool radius. A controller generates signals indicative of the tool paths and respective depths, and presents the signals to operate an automatic cutting machine and cutting tool to selectively remove material from a sheet material to produce the graphic images.