To this end, the thickness of the part of the index which covers the scale marks must not be greater than the thickness of the scale marks themselves. The index must be capable of covering approximately half the length of the shortest scale
marks. The maximum distance between the index and the plane of the scale marks must not be greater than the length of the scale division and must in no case exceed 2 mm or 0,02 L + 1 mm in the case of circular-dial indicating devices (L
being the distance between the axis of rotation of the pointer and its extremity).
