Exploded View of Parker Duofold

A look at a very popular, well designed and engineered fountain pen.

Parker Duofold Jr

Part of the beauty of the Duofold's design is that it is easily broken down into it's most basic components.  There is no need for any special tools (like an inner cap puller) to take this pen apart, this allows for damaged parts to be replaced easily.  The Duofold is also one of the simplest pens to repair, first you remove the blind cap at the end of the barrel and pull the button straight up and out without rocking it side to side (that could crack the blind cap nipple).  Next the pressure bar is eased out, they are designed to fit through the hole that the button is placed in.  After that you can open the pen, the threaded section makes it very easy to do.  Although it should be noted that 'streamlined' Duofolds have a friction fit section.

Streamlined Duofold Jr: the only difference is the friction fit section and the slightly tapered,  rounded off ends.  This pen also still has its original factory three-part pressure bar.

Duofolds were streamlined sometime around 1929 in an attempt to keep up appearances, competing pen makers had come out with radically streamlined pens and Parker wanted in on the action while retaining the Duofold's classic shape.  This pen model introduced sometime in 1921, although there was a similar model pen, the Parker Jack-Knife Safety that debuted in the late teens, utilizing the same basic shape and filling system.  The first Duofolds were made of hard rubber in either Chinese Lacquer Red (more burnt orange than anything, earned the pen the name Big Red), and plain black.  Celluloid or Permanite pens as Parker called it came out around 1925.  The Duofold was released in several sizes throughout the time it was on the market, oversize, junior (standard), a ladies ring top pen and a mens vest pocket ring top, there were also several variations on cap bands, the double band seen on the pens above being the most common.  Being a popular model the Duofold was on the market as a button filler until 1940, when is was drastically redesigned and released as a Vacumatic filler (more on Parker Vacumatics in a future post).

Left: Streamlined Duofold friction fit section.  Right: Original (flat-top) threaded section.

How Does it Work?

When the button is pressed, the pressure bar is forced down and bows outward, depressing the sac.  It's a very fool proof and failure proof filling system as there is little in the way of moving parts that can break.  When the button is released the bar goes straight allowing the sac to take in ink.  The original factory pressure bars have a lip that rests on the blind cap nipple, which holds the bar in place.  The new replacement are longer and rest against the section of the pen.

New Two Part Replacement Duofold Pressure Bar: When the button is pressed, the bar bows out depressing the sac.

Duofold Jr. seen above back together

Several Different Models- L to R: Flat-top 'True Blue' long, jade green Jr. streamlined, red flat-top Jr., chased hard rubber Deluxe Lady Duofold