Traction sheaves in modern elevators are subject to increasingly stringent demands. Machine room-less drives and thinner ropes significantly increase the loads on the keyways. Despite high manufacturing quality, they are subject to constant wear. This can lead to uneven wear in individual grooves, particularly with unevenly adjusted rope sets. Regular inspection is therefore particularly important. To monitor this wear, or to measure the wedge angle of the groove in worn traction sheaves, Henning manufactures a simple measuring tool that no toolbox should be without. Similar to a vernier caliper, it has a base with an angle scale and a movable part. To measure, the locking screw is loosened and the fixed measuring leg is placed against one side of the keyway. The movable part is then moved until there is no visible gap between the measuring leg and the groove flanks. During the inspection, the protractor must be held at a right angle to the groove. If the measuring jaws are parallel to the groove flanks, the measuring device can no longer "rock" in the groove. The measurement result can now be read on the protractor's scale.