A few millimeters goes a long way in pen design.

I learned that after introducing my "Mercury" pen model in October '22 at the Dallas Pen Show. I had visited my first pen show in just March of that year, in Baltimore where I was introduced to the Vintage pen market. I found that there were thousands of pens available in that one show which were produced in the 1920's through 1950's that all had a similar size to them. These pens from the golden-age of fountain pens all measured between 4-1/2" and 5" in length with a barrel thickness of about 7/16" or ~12mm.

This is a real practical size pen, especially for keeping in your pocket or purse, or for slipping into the loop of a notebook. 

But in the Custom Fountain Pen community, no one was making and selling this size pen. So I decided to change that........

Above is one of my "short" Mercury Pocket Pens with a clip. As you can see, the size is comparable to a "Kaweco Sport", Esterbrook Dollar Pen", "Pelikan 140" and a "Fifth Avenue" at ~123mm in length with a 11.5mm barrel diameter.

After introduction of this new "slim" model at the Dallas Pen Show, I expanded the line of Mercury pens to additionally offer a longer one, which at ~135mm (5-1/4") is close in length to my mid-sized "IKE" and my larger size "Liberty" as show below. 

So the relevant dimensions for these 3 pens are:

  • Liberty:
    • Cap diameter ~17.5mm
    • Capped length ~140mm long
    • 15mm cap to barrel threads
    • Section pinch ~11.8mm
    • Barrel diameter ~15.4mm
  • IKE:
    • Cap diameter ~16mm
    • Capped length ~ 135mm long
    • 13mm Cap to barrel threads
    • Section pinch ~10.8mm
    • Barrel diameter ~13.5mm
  • Mercury:
    • Cap diameter ~14mm
    • Capped length
      • "Long" ~135mm
      •  "Short" ~122mm
    • 11mm Cap to barrel threads
    • Section pinch ~9.2mm
    • Barrel diameter ~11.5mm

Size Matters


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