The Plunger Filler Exposed!

[Hobiwan]

Greetings, fellow Esty fans.

Back in February, antoniosz posted the following, regarding the “plunger-filler”:

 

https://www.fountainpennetwork.com/forum/index.php?/topic/143406-esterbrook-plungr-filler/page__p__1422742__hl__%2Bplunger+%2Bfiller__fromsearch__1#entry1422742

 

In that post, which contains very cool x-rays taken of the inside of the pen, some questions were asked, namely:

 

(1)What makes most of these pens found to be in fully operational condition while the Sheaffers and other vintage plunger fillers always are found almost always in need of repair?

 

(2)How is the sac attached?

(3)How to disassemble the plunger or install the sac

(4)How to take out the piston...

 

Well, in the interest of science, and satisfaction of my own curiosity, tweaked years ago when I first bagged one of these gems, and recently awakened by antoniosz’s post, I have done the unthinkable, and taken apart a good working pen. I haunted “feebay” for 2 months, and gobbled up two of the rattiest looking PFs offered, hoping to find a dog that I could justify disassembling. But did I get one? NOOOOOO! They both worked just fine! Sooo…..

 

Anyway, the following pictures and windy pontificatory explanations, together with a review of the prior thread, will, I hope enhance your understanding of this ingeniously put together 3rd generation of a crafty 1920s design.

Here's all the pieces and parts.

http://www.home.earthlink.net/~hobiwan/ebay/PF01.jpg

 

The piston and ring.

http://www.home.earthlink.net/~hobiwan/ebay/PF02.jpg

 

The Ink-Vue sac as a possible replacement.

http://www.home.earthlink.net/~hobiwan/ebay/PF03.jpg

 

 

To understand the Esty Plunger filler, let’s digress just a bit.

 

There are 3 main groups of what have been referred to loosely over the years as “vacuum fillers”. To save space and reduce the boredom factor, I’ve posted the entire analysis on my little website, here. http://www.home.earthlink.net/~hobiwan/ebay/VacuFil.htm

 

First, there are what I call “PUMP FILLERS”. Parker’s Vacumatic and early 51 pens, as well as Waterman’s Ink-Vue type fillers are examples. They use compression of a sac to pump out air, then expansion to suck ink into a sacless barrel.

 

Then there’s the only true “VACUUM FILLER”, in my opinion, the late ‘30s Sheaffer “piston filler”. You pull back on the knob to full extent and then push it forward, back to the barrel. The disk inside creates a vacuum behind it as you push in. At the end of the stroke, the disk reaches a wide spot on the inside, and the vacuum generated then sucks the ink behind the disc into a sacless barrel.

 

The third kind, simply designed and most efficient, are what I think should more properly be called “PRESSURE FILLERS”. These fillers first create pressure to compress a sac, then release that pressure to allow the sac to expand, sucking in the ink. The first of these I know of are the magnificent Chiltons of the late ‘20s and early ‘30s. Sheaffer later improved on the design with their Touchdown series, and later added the additional gadgetry with the Snorkel’s moving sac housing.

 

The Esterbrook “plunger fill” pen (I hate that description, by the way, makes me think of the many times I’ve had to unstop a toilet) is the third (and last, as far as I know) variation of pressure filler. True to the Esterbrook philosophy of “Keep It Simple”, it’s a successful marriage of two technologies; Sheaffer’s vacuum filler disc and Chilton’s use of the sac. Instead of vacuum behind the disc, it creates pressure AHEAD of the disc, to compress the sac. Then, releases the pressure with a wide spot in the inner diameter of the barrel at the end of the downstroke, allowing air into the pressurized “sac chamber” letting the sac expand to fill with ink.

 

Looking for a replacement sac, which I’ve NEVER had to do for this pen, was a puzzle. The White Rubber Company, which manufactured most all of the sacs used in fountain pens since 1919, closed down in the early 1980’s, and was revived a few years later by my good friends, Bob Tefft and Peter Amis. You can check it out here http://www.pensacs.com/index.html (no affiliation). But there’s no mention in their catalog of any sac that might fit the Esty plunger filler. As a substitute, I found a “short necked” large sac that’s used for the Waterman Ink-Vue, and a smaller one, used for the Lady Patricia Ink-Vue type fillers. I believe I’ve pictured the large one here, and it’s a pretty close fit, but it doesn’t fill the barrel like the original Esty sac, so won’t hold as much ink. See picture for comparison.

OK, now to answer some questions.

The creator of the pressure is a true piston. As you can see from the pics, it’s 2 discs, with a loose-fitting rubber ring that makes the pressure, just like the piston rings in a car engine.

Can you safely remove the piston? NO. To get it out, I had to break it. Luckily, it broke off inside the “blind cap” at the end, and I can glue it back together. The piston unit is 3 parts glued together: the double disk, glued to the shaft, glued to the blind cap. In the manufacturing process, I figure they first glued the disc/ring assembly to the shaft, then pushed it through the barrel, then glued on the blind cap.

 

How is the sac attached? The x-ray from the previus thread shows the sac glued on its outside at and below the neck to the inside of the section. I tried gently to remove it, but it's on very tough, so I suspect it’s an adhesive that’s stronger than shellac, because the stress on the joint is greater due to the pressure behind it. But I’d try shellac first and see if it holds up.

 

Why are these pens still operational while the Sheaffers, etc. most always need repair? Engineering genius! See the diagrams. Fig.1 shows the unit at rest, before the upstroke and after the downstroke. The piston is at its wide spot. The shaft of the piston is not sealed at the end of the barrel, thus air can pass through the opening into the barrel. The lower disc on the piston has two slots cut into it (Fig.1 insert). The ring (red) is loose on the shaft, so that on the upstroke (Fig.2) it rides against the lower disc, exposing openings at the slots, which are just inside the inner diameter of the ring. So, on the upstroke, air (purple) passes through the shaft hole, around the upper disc, and through the slots into the sac chamber. No back pressure at the shaft entrance, no vacuum in the sac chamber, therefore NO STRESS on the sac. The sac itself is thinner than a normal sac, so compresses easily with the pressure generated by the downstroke, and the open, necked design and fitting distributes the compression equally on all sides. On the downstroke (Fig.3) the ring now rides against the upper disc, creates a seal and compresses the sac with the pressure generated. It reaches the wide spot inside the barrel, everything loosens up, air rushes in through the shaft hole, pressure’s off, and the sac expands, sucking in ink (Fig.1).

 

http://www.home.earthlink.net/~hobiwan/ebay/PFdemo1.jpg

 

http://www.home.earthlink.net/~hobiwan/ebay/PFdemo2.jpg

 

http://www.home.earthlink.net/~hobiwan/ebay/PFdemo3.jpg

 

Altogether, it’s a stress-less, easy-going, efficient, economical little gadget-filler. All made out of a few pennies worth of plastic and rubber. Hat’s off, sez me.

 

Now, if I can just glue that piston back together....

[777]

Thank you!

 

Very informative and useful. Answered many questions for me. Good job on keeping it simple and not confusing!

 

Now, the question is: how soon can I snap one of these up ebay... me wants one...

 

Regards,

777

[Ernst Bitterman]

That is a magnificent act of scholarship. I've been pondering mine for months in a paralysis of uncertainty, but now I can at least contemplate a re-sacking. Based on your examination, would you see any utility in getting a little silicone grease into the piston chamber?

[pal38]

Thanks a lot, Hobiwan!!!

 

For some time now I have been preparing a post trying to shed some light into the Safari plunger filler, looking at the pen from every angle. I just couldn't get wise without taking apart the pen. Well, you did it! Hat off!

 

There was a time I thought of going into collecting Sheaffers, but their damn plunger fillers succeeded to put me off. Finally I know now why Estie plunger fillers outlast by far their more famous and expensive mates.

 

:notworthy1:

[M@rtin]

Maravilloso

[hari317]

Thank you for this excellent article Hobi!

[Hobiwan]

That is a magnificent act of scholarship. I've been pondering mine for months in a paralysis of uncertainty, but now I can at least contemplate a re-sacking. Based on your examination, would you see any utility in getting a little silicone grease into the piston chamber?

 

I wouldn't if I had decent pressure on the downstroke. Either see how many drops it takes in when you re-sac or do the finger (or toungue) test at the barrel opening to see if there's a decent "push". Some of that stuff they put in Sheaffer TDs might work without hurting things (all speculation on my part, not having had the opportunity or necessity to do so).

[Hobiwan]

Thanks a lot, Hobiwan!!!

 

There was a time I thought of going into collecting Sheaffers, but their damn plunger fillers succeeded to put me off. Finally I know now why Estie plunger fillers outlast by far their more famous and expensive mates.

 

:notworthy1:

 

The Sheaffer Touchdowns (the ones with the fat sleeve instead of the skinny-stemmed piston) are a real easy fix and a high-quality pen, if the nib is good. I always thought that that's about as far as they should have taken the technology, but no, they HAD to add the snorkel. Too many engineers with nothing to do ....

[kathleen]

My Esterbrook Safari Plunger filler works perfectly but I do not like this pen. I much prefer my Esterbrook J series pens. I find little to recommend the Safari.

Hobiwan, it was quite interesting to get such a detailed and well illustrated explanation of the innards.

 

[fountainbel]

Very interesting, never seen such a filling system.

Thanks for shearing !

Francis

[Hobiwan]

My Esterbrook Safari Plunger filler works perfectly but I do not like this pen. I much prefer my Esterbrook J series pens. I find little to recommend the Safari.

Hobiwan, it was quite interesting to get such a detailed and well illustrated explanation of the innards.

 

 

I don't think you'll have any trouble at all selling/trading your Safari for any J-series pen you choose. Uh...whatdya need?

[Federalist Pens]

Thanks for the tips, and info Hobi!

I have a Safari Plunger as well that needs to be restored, but I have not tried to open it.

I may have to reconsider the advice I received NOT to open it, at the risk of breakage!

 

Regards,

Frank

[DanDeM]

Another print-out as an addendum to Hobi's book.

Many thanks.

[kathleen]

My Esterbrook Safari Plunger filler works perfectly but I do not like this pen. I much prefer my Esterbrook J series pens. I find little to recommend the Safari.

Hobiwan, it was quite interesting to get such a detailed and well illustrated explanation of the innards.

 

 

I don't think you'll have any trouble at all selling/trading your Safari for any J-series pen you choose. Uh...whatdya need?

 

Between my son and I, we have a nice array of Esterbrook pens beginning with a Hard rubber Dollar pen through to some Icicles and those pens made in the final days of Esterbrook before its buy out by Venus. We only have the one Safari, an example of what Esterbrook produced in 1957.

I really like writing with all my Esterbrook pens, Dollars, Transitionals, Js, all except the Safari. The Safari just feels wrong, too light and unbalanced when posted. I know I'll be called the "c" word, but I'll be keeping the Safari even though I do not like it.

[Hobiwan]

My Esterbrook Safari Plunger filler works perfectly but I do not like this pen. I much prefer my Esterbrook J series pens. I find little to recommend the Safari.

Hobiwan, it was quite interesting to get such a detailed and well illustrated explanation of the innards.

 

 

I don't think you'll have any trouble at all selling/trading your Safari for any J-series pen you choose. Uh...whatdya need?

 

.....

I really like writing with all my Esterbrook pens, Dollars, Transitionals, Js, all except the Safari. The Safari just feels wrong, too light and unbalanced when posted. I know I'll be called the "c" word, but I'll be keeping the Safari even though I do not like it.

Ah, I understand that, Ms. "C" . They're all part of the history. I felt similarly about the "cracked ice" pens -- too delicate, not very practical. Dropped a white one on the table one day from about 4 inches and the barrel cracked at the section from that little bit of stress. Held on to them though ....

[TETRIS]

Hello Hobi,

 

Great to see the Esterbrook "plunger filler exposed", thanks!!

 

In your post there is a refence to the only one true plunger filler, the Sheaffer's plunger filler.

 

The first, that I know, was Onoto, or Thomas De La Rue pens. Sheaffer copied the system. In the US, Conklin and Eversharp used it, among others.

 

The filling system used by Esterbrook, the one you show here, was also in use by Fratelli Rossi, in Italy, early 50's, on the Penco pens, was the same design. Don't know who got it first. I think the pen was the Penco 53.

 

Best,

 

Victor

[Hobiwan]

Thanks, Victor, for pointing that out. Never heard of the Penco before now.

 

I mentioned the earlier Sheaffer as a vacuum filler, not plunger, and was referring to, I guess, the main driving force for "inhaling" the ink. The others used a rubber sac/membrane to expel air/suck up ink, while the Sheaffer used vacuum force inside the barrel alone to do the job. So, while the Parker, for instance, called its pen a "vacumatic", the action to fill the pen was more "pump" rather than "vacuum" alone.

 

And I grouped the Chilton, Touchdown and Esterbrook as "pressure fillers" only because they all exert air pressure to compress the sac, rather than a lever-on-J-bar or other mechanical "squeeze the sac" approach.

 

Not being an engineer or knowing the proper terms for all that, the above organizes the subject in my own head, and I move on less confused.

[Rabbit]

Thank you for risking the life of one of these to show us what's inside! I've always wondered if the blind cap was removable (without breaking it), and now I know that it's not. Great information!

 

--Stephen

[ticoun]

Thanks, Victor, for pointing that out. Never heard of the Penco before now.

 

I mentioned the earlier Sheaffer as a vacuum filler, not plunger, and was referring to, I guess, the main driving force for "inhaling" the ink. The others used a rubber sac/membrane to expel air/suck up ink, while the Sheaffer used vacuum force inside the barrel alone to do the job. So, while the Parker, for instance, called its pen a "vacumatic", the action to fill the pen was more "pump" rather than "vacuum" alone.

 

And I grouped the Chilton, Touchdown and Esterbrook as "pressure fillers" only because they all exert air pressure to compress the sac, rather than a lever-on-J-bar or other mechanical "squeeze the sac" approach.

 

Not being an engineer or knowing the proper terms for all that, the above organizes the subject in my own head, and I move on less confused.

 

the conklin nozac Q.F (quick filling), some wahl-eversharp dorics and some onoto pens were also true vacuum fillers. the onoto was the first of them, and was the inspiration for the others.

[antoniosz]

Excellent. Thank you very much

I am glad that I managed to wake up a sleeping (?) giant of Esterbrook penology :) :)

 

But is it really engineering genius? I have the vague feeling that it is more marketing/sales genius. Without the possibility of removing the blind cap, the pen had to be replaced (or at least the barrel). If they had made the rod threaded into the blind cap, repair would have been much easier. Of course most of these pens dont need repair!...

The only problem is the shrinkage of the rubber ring. If there was a way to replace it, the few of them that dont work, they would come back to life

 

So I presume that heat did not do any good in removing it, right?