The Parker 51 Vacumatic is a great pen, IMHO, as they say. I like everything about them, including the quirkiness of the filling system. In the Parker repair manual instructions are given for the filling of a 51 Vacumatic compared with the Parker Vacumatic pen:
There is one major difference in the filling methods of the Parker «51» and the Parker Vacumatic. The difference is that after the Parker «51» has been completely filled (usually after ten strokes of the plunger), the excess ink must be withdrawn from the fins of the collector. To accomplish this, the filling instructions of the Parker «51» say, «On the last stroke hold plunger down and then lift from the ink. When the pen point is out of the Ink, release the plunger.» This last operation clears excess ink from the collector.
You may be surprised at 'ten strokes of the plunger', I suspect many 51 Vac owners are shortcutting the filling process!
The three pens here are, from at the top:
Parker 51 Vacumatic. U.S.A with Sterling Silver cap, Blue Diamond clip, Cedar Blue 1944.
Parker 51 Vacumatic U.S.A with Lustralloy cap, Blue Diamond clip, Cedar Blue, 1947.
Parker 51 Vacumatic England with Lustralloy cap, transition (long) clip, Black, c. 1948.
