A plunge base router for use in an upright and an inverted position is disclosed. The router includes a depth adjustment mechanism, a depth stop mechanism, a post lock mechanism, and a return spring defeat mechanism. The depth adjustment mechanism includes a course adjustment mechanism and a fine adjustment mechanism to set the cutting distance of a bit. The course and fine adjustment mechanisms are usable in both the upright and inverted positions and the fine adjustment mechanism is operable without being reset throughout the full range of motion of the plunge router. The depth stop includes a mechanism for locking the end of a rod on the housing to the base in order to set the relative position in between the housing and the base. The depth stop also includes a plurality of steps for engaging the rod and permitting incremental passes of cutting at different depths with the router. The post lock mechanism includes a lever for locking the housing to the guide posts in a relative position relative to the base, and the lever is normally biased to the lock position. The lever includes a latch for locking the lever in the open positions so that the plunger can be easily mounted in an inverted position under a worktable without the need to hold down the lever in order to permit relative movement between the housing and the base. The return spring defeat mechanism defeats the return spring that biases the housing away from the base so that it is easier to mount the plunge router in an inverted position on the underside of a worktable.