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Parker Button Filling Mechanism
by Jim Mamoulides 1/12/02 - Updated 9/10/02

No Breaks In The Barrel

Parker developed the button filling system in 1916, a clever design that avoided legal and design problems in copying or redesigning Sheaffer's lever-filling system and allowed for production of clean bodied pens, since the filler operates by pressing a button at the end of the barrel. The button is concealed from view under a screw-on cap. The cap is called a "blind cap" and this filling method is called "button filling." Parker advertised this as a feature - the pen had an "unbroken" barrel. Button-fillers proved as efficient as lever fillers in operation, so Parker pens were strong sales rivals to Sheaffer pens. Parker adapted the new filler to the successful Jack Knife Safety line, but it was the Duofold that is most strongly associated with this system.

Detail From 1926 Parker Duofold Advertisement Showing Filling Instructions

The button-filler was used on several following pen lines, such as the Challenger and Thrift pens of the 1930s, the Duofold Geometric, and striped Duofold of the 1940s. The clean lines of the button filling system became something of a Parker design theme, with the Vacumatic pens of the 1930s and 1940s also having a blind cap and plunger at the barrel end.

How It Works

Detail of Parker Duofold Filling Button With End Cap Removed

The button-filler is a very simple design that actually works very much the same way a lever-fill pen works. Inside the barrel is a long sac that holds the ink. Alongside the sac inside the barrel is a long flat springy bar that bends at the base of the barrel and terminates into the back of the button. When the button is pressed, the bar is bent inward and compresses the sac, expelling its contents. As it reinflates, if the nib and feed are in ink, the vacuum created will fill it. A lever-fill pen does the same job by directly pressing the bar from the side of the barrel.

How To Fill Your Button Filler Pen

Getting A Parker "Big Red" Oversize Duofold Ready To Fill

Duofolds and other Parker pens that use the button-filling system are very simple to fill, but to a novice this may not be intuitive without the instructions. The pen has no lever, by design, giving the pen a clean, unbroken barrel and the blind cap hides the button.

Parker Duofold Filling Instructions Included With the Pen c1926 - Sized for Printing

Button fillers are simple pens to fill and use, as these instructions packaged with the Duofold show. The process is straightforward: remove the end cap, dip the nib in ink, press the button once, count to ten, and remove the nib and wipe.

This same set of instructions applies to any Parker or other similar button filler. Some later button fillers (after 1940 some button fillers were equipped with a breather tube) may require two complete cycles to completely blow the air out of the sac and completely fill. This second cycle is also common for some breather tube equipped lever fill pens.

Comments on this article may be sent to the author, Jim Mamoulides

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