The invention is essentially a quick-change blade carrier for a blade mounted to a rotary drive shaft (such as on a mower) has an internally threaded bore. The carrier includes a housing linked by its cap to the rotary drive shaft, and enclosing a blade-locking member having a blade-locking tip downstanding from its underside the device also includes a locking means (such as a compression spring) to bias the blade-locking member (and tip) downward through a center hole in the blade held within a channel in the bottom of the housing.