A new press mantle of a roller for water extraction from a wet fiber web, of paper or cardboard, has grooves (14) or blind drillings at the roller mantle surface (12). The side walls (18) are chamfered (20) and/or rounded (20') on a curved line at the opening, to prevent compression of the opening when the mantle is under pressure. The chamfer (20) edge length (y), towards the depth of the groove/drilling, is 1-3 times and preferably twice the edge length (x) along the longitudinal direction. The chamfer edge length on the longitudinal line (x) is 0.1-0.3 mm, especially 0.2 mm. With a rounded opening edge (20'), the length (y) of the edge in relation to a tangent is 1-3 times, preferably twice the edge length (x) along the longitudinal line which is 0.1-0.3 mm and preferably 0.2 mm. The chamfered/rounded edge (20,20') length (y) towards the depth of the groove/drilling is set to give a cylindrical wall section (24) between the base (22) of the groove (14) or drilling and the start of the chamfered/rounded edge. The curvature of the rounded edge (20') follows a circular arc or an involute. The chamfered/rounded edge (20,20') is at the outer edge of each groove (14) or blind drilling, or it is offset inwards towards the depth by a given gap from the mantle surface as a ring step.
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