Auxiliary handle installed on the casing (11) of a drill (1) having a drilling axis (Xo), incorporating an electronic acceleration meter (231), with axes (XoYoZo) defining a reference point; one (Xo) of the axes being the drilling axis; the other axis (Yo) being that of the handle (2); and a reference surface (SR, SR1-SR3, 3, 4) associated with the reference point of the acceleration meter (231) to register the relative position between the surface to be drilled (S) and the drill (1), and calculate the set position of the drilling axis (Xo), and a display (25) to show the set position of the handle (2) calculated from the set position of the drilling axis (Xo) to execute the drilling.

Various embodiments of power tool and method of operating same are described. The power tool may include a first position sensor, a second position sensor, a third position sensor, and a controller. The first, second, and third position sensors may each generate a signal indicative of a distance between the respective position sensor and a workpiece. The controller may determine one or more angles of the power tool with respect to the workpiece based on the first, second, and third signal and present an indication as to whether the one or more angles are within a predetermined range. The controller may further obtain a depth measurement based on the first signal, the second signal, and the third signal and generate, based on the obtained depth measurement, one or more control signals that control operation of the power tool.

Various embodiments of power tool and method of operating same are described. The power tool may include a first position sensor, a second position sensor, a third position sensor, and a controller. The first, second, and third position sensors may each generate a signal indicative of a distance between the respective position sensor and a workpiece. The controller may determine one or more angles of the power tool with respect to the workpiece based on the first, second, and third signal and present an indication as to whether the one or more angles are within a predetermined range. The controller may further obtain a depth measurement based on the first signal, the second signal, and the third signal and generate, based on the obtained depth measurement, one or more control signals that control operation of the power tool.

A PCB backup plate preparation method comprises: lubricating and radiating resin is coated onto both surfaces of the wood fiberboard and a resin layer forms, before it is totally dried out, wood pulp paper is bonded to its surfaces, then, the surface of the wood pulp paper is coated with unsaturated polyester resin and forms a resin layer, and the PCB backup plate is prepared; the lubricating and radiating resin is prepared by a 95 weight portion of principal component, composed by two or more of polyethylene oxide, polyethylene glycol, glycerol, vinyl acetate and polyvinyl alcohol, and a 5 portion of nonionic surfactant. The lubricating and radiating resin brings the PCB good lubricating and radiating capabilities, therefore increases the drilling hole accuracy when starts to drill, improves the hole wall quality and lowers the drill pin temperature.