Those machine marks hold more lube than you think Jon. And in a travel press or one used in nasty conditions a thicker than normal lube may be good to consider. a heavy wax based grease may help seal water and crud out of the ram casting joint. I might even consider checking the wall thickness of the casting and if thick enough drill and tap for a 1/4 28 grease zerk. This would allow easy lubing and for grease to be used to push crud out easily.