The Filling System Riff

Some of the terms used in describing fountain pen filling systems are less than helpful in understanding how the pens work.  For instance, Parker’ Vacumatic and Sheaffer’s Vacuum Filler seem to lay claim to the vacuum principle in filling pens, whereas every pen that has a self-filling system depends on that principle.  Whether they be sac fillers, piston fillers, plunger fillers or any other self filling system I’ve forgotten they are provided with a means of creating a vacuum and it is nature’s abhorrence of that vacuum that fills the pen.  None is more dependent or makes greater use of the vacuum principle than another.  All self-filling pens are vacuum fillers.

“Twist Filler” must be the most misused term of all. In a true twist filler, the sac is attached at both ends, one directly to the turn-button on the end of the barrel.  When the button is turned, the sac is wrung out like a dish-cloth.  The defining principle of the twist filler, then, is that the sac itself is twisted to empty it of air in preparation for pulling in ink.  Almost any pen that has a turn-button on the end of the barrel seems to be called a twist filler nowadays, whereas the majority of them work in another way.  Swan’s Leverless is often called  twist filler, but in fact the sac is attached at only one end and rather than being twisted it is pressed against the interior of the barrel, thereby expelling most of the air.  Various late Mabie Todd pens are called twist fillers when in fact they are most closely related to the button filler.  A cam is activated by turning the button, and this presses down on a normal pressure bar which squeezes the sac in the usual way.

Yes, I’m feeling picky and pedantic today.

11 thoughts on “The Filling System Riff

  1. Deb,

    I appreciate that you occasionally use your blog to display your educational bent. It’s a great service to those of us who are sadly ignorant of the mechanics of our objects of joy.


    1. Some of these terms that we use all the time are actually ill-defined and can lead to confusion. I saw a couple of examples recently where people were misreading what they saw, and it spurred me to try to clarify the terms. I won’t educate the world, but maybe a few here will understand a little better what is and isn’t a twist filler.

      1. Ah but Deb. I am waiting for Part 2 where you come up with appropriate descriptors of those other systems.


      2. There are an awful lot, Philip, and most are straightforward. I wrote about these two examples because I kept seeing the names used incorrectly and causing confusion. If there are others in a like category I could try to demystify them, but such things as lever and button fillers, Aerometics, crescent fillers and so on are very well covered elsewhere and most, I think, will be well-known. A series of articles on common filling systems might educate and entertain a few, while boring the rest to distraction. And then there’s always the possibility that when I get into the arcana of the Ford Patent Pen or the second version of the Visofil my scholarship might run a tad thin… There are some heavyweight pen people who read this blog, y’know.

  2. Ok Deb. Here was what I was thinking. If a twist filler has the sac anchored at both ends then how what would you call something like the Stephens Royal which has a regular sac but the button turns the press bar much like the Swans. is there or could there be a variation on “twist filler” which would nuance that kind of mechanism. I look to those heavy hitters to weigh in.


    1. That’s an easy one – like the Late Swans/Blackbirds it’s a variation on the theme button-filler. In a twist-filler, the “twist” applies to the sac. If it applied to a button or a stud then piston fillers, Onoto Plunger fillers, Leverlesses and various button fillers would all be twist-fillers and we would be in definition chaos. It’s one of these situations where external appearances are misleading. Are we twisting that button to enact some other process or to simply wring out the sac? If the real filler is a moving piston or a sac compressed by another moving part then the twisting is of subsidiary importance to the action it sets in process.

    2. Hi Philip,
      I realise I slipped up rather badly replying to this comment the other day. Some days I don’t take things in too well! Clearly, if the Stephens Royal’s mechanism closely resembles that of the Leverless, it must be categorised in the same way: not a twist filler as the sac is not twisted but compressed. I had completely forgotten about the Stephens Royal and I’ve never seen one – apart from photos of its exterior on a sales site. Does it resemble the Leverless in its workings so closely that it must have been made under that patent? Given that Stephens didn’t make their own pens, who made the Royal? It looks quite like a post-war Swan, but we’ve seen before that resemblance can be a red herring.

  3. Hi Deb,
    No worries.From what I have read the Royal does work like the Leverless. I have just received a French Stephens that is larger than any Stephens I have ever seen. It is in fact longer than a MB 149 or even a MB Franz Kafka. It is a tidge thinner than than the 149 and comes with a hooded nib shell that is a little reminiscent of the Mentmore 46. I will send you some pictures in the next day or so. This pen also has that turning bar filling system. I suppose we could just call all those systems leverless but that seems to encroach too much on the Swan identity.
    I wonder if, for absolute clarity, we should try and come up with a particular name that would identify this particular system and thus try and get away from the mis-leading Twist filler sobriquet.


    1. That’s very interesting, Philip. I understand that these late French Stephens pens were actually made by Jif Waterman. I would love to see pictures of that rarity, and if you can show the innards, so much the better. The Royal is, I would guess, somewhat older. It would be interesting to know who made it and what patent applied to the filling system. It seems likely that the same patent applied to this hooded nib pen. Compressor bar? Someone once described it as an “entangling bar” but that isn’t what it actually does, if you watch it in action (not an easy thing to do – I had a Leverless with a large hole in the barrel!) it flattens the sac against the barrel interior. I need to get my grimy paws on one of these strange Stephens, just to see this mechanism for myself. I’ll be on the lookout for one…

  4. It turns out I was wrong about twhat I am calling the Stephens Grand. It doesn’t have the compression type turning system but has a variant off the button filler whereby you turn the blind cap and it drives a small shaft down that compresses the pressure bar.
    You can see the pictures here:
    You can also see the size comparison to the MB 149 and Kafka.

    Looks like I should take apart one of the Royals to show the other mechanism.

    1. That’s a pen that will raise eyebrows wherever it goes, and not just because of its large size. The hood is, as you say, very reminiscent of the Mentmore 46 and the clip has a decidedly Watermanish look about it. The filling system seems to be the same as was used on the nineteen-forties stud fillers. Weird and wonderful, and, I think, a very great rarity. I’ve certainly never seen one before, nor have I even heard a whisper of its existence. It would be good to know (though we never will) whose brainchild this pen was. That hood has no ancestry in Stephens’ pens nor in Watermans, so far as I’m aware. It just appeared fully-formed and judging by its rarity, it disappeared equally quickly.

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