I built this about a year ago as an exercise in old part reuse, and as a test of how stable FreeCAD was. It is only strong enough to push low viscosity liquids and pastes. Some Mk2 improvements would be to add gearing to the motor to increase pushing force, constrain the plunger pusher with two more bearings to provide for effective retraction, and use one of the old limit switches to zero the plunger position.