A positioning station supports a sand mold half while centering using two sets of moveable arms. A gripping structure having two inwardly facing pads are each mounted for rotation about a common axis on separate axles. The pads remain in a fixed angular relationship to one another throughout rotational movement. Each pad has plural individual compressible fingers and a fixed fulcrum structure pointing inwardly towards the opposite pad and adapted to grip a sand mold half by engaging the surface of the sand mold half. The gripping structure is lifted away from the platform sufficient to allow a second sand mold half to be placed on the platform and then the gripping structure is lowered to accurately mate the two mold halves.