A power tool assembly includes a drop arm frame with an opening configured to rotatably support an arbor shaft, a lower surface spaced apart from the opening, and a plurality of ribs extending between the lower surface and the opening. The plurality of ribs define a respective one of a plurality of axes, the plurality of axes intersect at a locus, and the locus is adjacent to, but spaced apart from, a center of gravity of the drop arm assembly. The power tool assembly further includes an actuating device configured to transfer a force to the drop arm assembly when the drop arm assembly is at the first drop arm assembly position, and a control system configured to control the actuating device to transfer the force to the drop arm assembly when an unsafe condition is sensed.