A quick-changeable mowing blade (22) is provided with a shaped feature (36) and a hole (34) which maintain a certain spacing X from one another. For installation, the mowing blade is held, by means of the hole, pivotally on a head (44) of a peg (38). If the head undergoes an impermissible amount of wear, the shaped feature is no longer hidden by a cover (52) of the mowing cutter disc (20) but becomes visible.
