A fixing member comprises a threaded end, one end face of which contains a recess capable of housing a tip, complementary in shape, said recess comprising a peripheral edge in the form of a multilobed continuous curved line. The cross-section of each lobe L is defined by a continuous series of three arcs of a circle, i.e. a first convex arc of a circle with a first radius (R1), on either side of which a second concave arc of a circle with a second radius (R2) are positioned. Each lobe is connected to the adjacent lobe via a third convex arc of a circle with a third radius (R3, R3u) larger than the first radius (R1). The invention also relates to a male element with a raised shape complementing that of the recess, in addition to a handling tool and a testing gauge comprising such a male element.