The Esterbrook #3556 Firm Fine nib is my only 3xxx series nib.These are often referred to as “Sunburst” type nibs due to their elaborate engraving on the nib.
These were the first Esterbrook nib that had tipping material, which Esterbrook called Osmiridium. Osmiridium is a rare alloy, although I haven’t been able to find out if Esterbrook used the natural alloy or made there own from osmium, iridium and maybe a little platinum. Later 9xxx series nibs were also Osmiridium tipped. According to Paul Hoban’s Esterbrook book “The Fountain Pens of Esterbrook” the #3556 nib was one of four 3xxx series nibs introduced in 1938. The osmiridum tipped nibs 3xxx nibs were identified with a red sleeve (the part that slides into the pen). The nibs were phased out by 1944. The 8xxx series nibs also used the Sunburst design but were gold plated and Palladium tipped. Some of the 3xxx series nibs were made in the UK, were gold plated and lacked the Sunburst design. although the #3556 is not one of these.
My particular Esterbrook #3556 is a smooth writer. True to its “firm” name there’s no spring to the nib. There wasn’t any skipping or false starts and it was a consistent writer.
My nib has the early flat feed design which makes sense since Esterbrook probably stopped manufacturing these when they introduced the wartime design feed. There was some nib creep, of sorts, ink liked to jump out to the wings of the nib as if following the rays of the sun.
While the tipping material may provide more durability, I found the untipped #2556 to provide just as good of a writing experience. And as to durability, I suspect even the untipped nib will outlive me.
The 3xxx nibs in general are hard to find and the Esterbrook #3556 is no different. I did see one listed on eBay for $50 and another being sold with a Dollar pen for $80.
The Esterbrook #3556 firm fine nib is a winner in my book simply because it has two of my favorite nib related words in its name. The Sunburst logo provides something to admire when it’s being used. But based strictly on the writing performance I find the #2556 to be its equal, despite the lack of tipping material.