Jolly was made to satisfy "WATER JET CUTTING MACHINES" builders' and oweners' exigences. Its aim consist in feeding the nozzles of the callipers without stopping the system, avoiding then remarkable loss of time. Our propeller soley studied and projected to work this problem out. The automatic chargingsystem, rum from a sensor driving the operation, takes the times of 18'' adjustable, in these times the discharge of the tank, the filling and the re-starting of the machine, allow the residual abrasive in the callipers to make the cutting process of any product go on without alteration.