Abstract: A blade assembly for weed trimmers for cutting heavy weeds, vines and underbrush comprises a seamless, one-piece, disk-shaped hub. Pivot pins attach two or more steel blades to the hub within a circumferential groove. The groove extends from the outside edge of the hub towards the center of the hub. The upper and lower portions of the hub above and below the groove support the blades vertically. The blades are free to pivot in a horizontal plane when they strike an object. The groove depth is at least one half of the blade width to provide vertical support. The blades are at least one half of the hub diameter. The blades are spaced equally around the circumference of the hub.