SAPPARTS recommend that tests be carried out to find the most appropriate setting. Since the O-Ring is always oversized to the housing, the edges of the housing must be rounded. Surfaces Under pressure, elastomers adapt themselves to irregular surfaces. However, for liquid-tight conditions, certain minimum requirements have to be made on the surface finish of the faces to be sealed. Scores, scratches, pores and concentric or spiral machining scores are not permissible. For the surface of the seal installation chamber we recommend a machining quality of mechanical face seals.