A power tool comprising a housing displaceably mounted to a foot plate, a blade, a motor, an electric switch and an interlock for controlling movement of the housing with respect to the foot plate. The interlock has a control button mounted to one of the housing or foot plate which cooperates with a channel fixed in relation to the other of the housing or foot plate. The control button can select between a plunge cut mode wherein the blade can protrude below the foot plate, or a blade change mode wherein the blade is prepared for a blade change operation. The channel comprises a major leg in communication with a minor leg. Cooperation between the control button and the major leg selects the plunge cut mode. Cooperation between the control button and the minor leg selects the blade change mode. The interlock may also comprise a housing lock and a spindle lock.