Abstract: A machine tool base and carriage system in which the base provides intersecting, vertical walls at its side margins each carrying and forming a rail having a head and toe pair defining bearing surfaces for carrying a respective workpiece or tool holding carriage slidably supported thereon for movement towards and away from the plane of the other wall respectively and in a horizontal plane. The base thus forms a single unitary triangular structure of horizontal operating arrangement, which may be integrally formed, and which presents the shortest possible bending moments for forces incurred during machining operations a kinematic mounting of the carriage to the base.