Abstract: An apparatus to make articles, in particular bottles, from parisons in a blow mold operation. The parisons are carried on transfer mandrels throughout the operation. The parisons riding on the transfer mandrels are heated while travelling around on a first wheel and are transferred into blow mold units mounted on a second wheel. Each blow mold unit is provided with an expanding mandrel which is extended through the transfer mandrel into the parisons. Two different blowing pressures are used in the blowing step which is controlled by cam controlled valves. From the second wheel the mandrels carrying the blown articles are transferred to an output wheel where the articles are removed from the transfer mandrels which are returned to the first wheel.