All major pen companies, American, Japanese, German, and Italian have or are producing demonstrator pens. The success of clear and durable plastics has made the production of great see-through pens plentiful and common place.
The interest in how pens work is not a new phenomenon, pen manufacturers dating back as far as the 1920’s were eager to show off their unique filling systems, clip assemblies, nib and feed improvements and the ability to seal the nib inside the cap (safety pens). Thus all of the major manufacturers provided their sales representatives with hard rubber pens that were cut away to reveal the inner workings. This being the origin of today’s demonstrator pens.
Original functioning demonstrators
Parker demonstrated the button filler by incorporating a window into the side of the barrel, allowing a view of the pressure bar compressing the ink sac when that button is depressed. Sheaffer did the same with their lever filled pens. In the days of vacumatic pens, models were made using clear materials (I guess acrylic), thus maintaining the integrity of the barrel so that the filling mechanism could be observed in action without having to damage the pen. Today, these vintage demonstrator pens are uncommon, considered rare and collectible, hence I decided to make my own cut away demonstrator.
I bought an Arnold lever filler pen and removed the side of the barrel, don’t worry it is a 21 cent pen that I paid $5 for….. wait hmmm, I guess a sucker is born ever minute. Anyway, I got out the Dremel and proceed to remove a bit too much of the barrel but that oops provides us with a better view of the inside.
On a side note, as the barrel was cut it did not melt, it turned to powder and caught fire. Nothing melted and notice that there isn’t any scorch marks on the barrel. This leads me to believe the pen is celluloid opposed to a plastic resin.
The ink sac is the largest component inside the barrel – surprise, it connects to the section near the cap teeth and runs the length of the barrel. Running parallel along the top of the sac under the lever is the pressure bar (aka J-bar). The lever is held in place by the snap ring, visible here bisecting the center of the barrel.
The mechanics of a lever filler pen is very basic, actually all fountain pens with an ink sac work by the same essential principle, a mechanism acts on a pressure bar which depresses the ink sac, when pressure bar is released, the sac expands to its original size and takes in ink.
Now you know the rest of the story.