An adjusting device for lifting and lowering a workbench is provided between a workbench and a workbench rest. An adjusting seat is firmly secured with the workbench rest and an adjusting wheel is screwed and locked on the adjusting seat. A screwing fastener is inserted through the underside of the workbench and the adjusting wheel, and an elastic member is provided between an upper flange of the screwing fastener and the topside of a fixed plate of the workbench. Thus, by the prestress of the elastic member pushing against the workbench, the workbench can be surely driven by screw rotation of the adjusting wheel and hence the adjusting wheel can easily drive the workbench to move up and down.

A router includes a motor unit, a base that receives the motor unit, a threaded shaft supported on one of the motor unit or the base, and a slide supported on the other of the motor unit and the base. The slide engages with the shaft in a first position of the slide in which micro-adjustments to a cutting depth are permitted. The slide disengages with the shaft in a second position of the slide in which macro-adjustments to the cutting depth are permitted. The router includes a lever movable to an unlocked position in which the lever disengages the slide from the shaft to permit macro-adjustments.