Machines for production of pipes, consisting of plastic and metal to be used for drainage areas, for canal and waste water drainage systems, for cable protection, for air-conditioning and ventilation systems, and for construction and building of chimneys, and structural parts and fittings therefor; Machine tools, namely, clamps for use in the precision clamping of work pieces, and structural parts and fittings therefor; machines for production for tubings made of plastic by blast extrusion pr...