An injection molding machine can include a base, a stationary platen fixed to the base for holding a first mold section and a moving platen for holding a second mold section. The moving platen can be slidably supported on a platen slide surface fixed to the base. The injection molding machine can also include a stack mold carriage for holding a mold center section. An actuator can be coupled to the stack mold carriage for translating the stack mold carriage along the machine axis towards and away from the stationary platen, the actuator comprising a driven member coupled to a carriage connection portion. The carriage connection portion can transfer motion from the driven member to translation of the stack mold carriage. The carriage connection portion can be joined to the stack mold carriage at an elevation below the platen slide surface.