There is disclosed herein drilling apparatus, in particular for use in the field of oil prospecting, comprising: a first tubular member (1, 2, 3); a second tubular member (6, 7, 8, 9) mounted at least partly within the first tubular member so as to be reciprocally free in rotation with respect to the first tubular member about an axis (5); and a drill bit (4) operatively connected to one of the first or second tubular members so as to be rotated in response to the one tubular member being turned in order to effect drilling, characterized in that: the drilling apparatus further comprises a restoring member (18, 36) for applying a forces between the first tubular member and the second tubular member at least in respective first axial directions in response to relative displacement of the first tubular member and the second tubular member in the respective opposite axial directions. Also provided are a tubular assembly and a method of assembling tubular members.