Leonardo Flex Nib Fountain Pen Comparison

Flex nib fountain pens are like cars that use a stick shift - they become rarer with each generation.

Yet, they are appreciated by those who use them most often. As you can already guess, I love writing with leonardo flex nib fountain pens. With a little pressure, a leonardo flex nib can add flourish and flair to everyday handwriting.

Yet, flex nibs are not all that common. At least, not as common as other popular nib sizes like F, M, or a 1.1mm stub. This looks to be changing. This year, German nib manufacturer Jowo introduced the steel elastic nib through the Leonardo Officina Italiana brand.

Since I already have experience writing with the 14kt gold version of the elastic fine nib, I'll offer a side-by-side comparison of both the steel and gold elastic nibs so you can decide which is best for your flexing needs.

How to test a flex nib

For this writing comparison, I inked up the Leonardo Momento Zero Giada Jade fountain pen fitted with the steel elastic fine nib with Diamine Kelly Green. The same ink also went into a Momento Zero Grande Mosaico Hawaii fitted with a 14kt gold elastic fine nib.

When evaluating a flex nib fountain pen, there are several details to observe.

1. What is the thickness of the line flexed versus unflexed?
2. How much hand pressure is needed to flex the tines?
3. How quickly does the nib "snap back" from being flexed?
4. Does the ink keep up or does it starve/railroad?
5. How smooth is the writing experience?

Flexed vs. unflexed line thickness

To test the flexibility of the nib, I wrote with both pens, applying as much pressure as I think the leonardo flex nib could handle safely without splaying the tines. Your results may vary depending on how much pressure you apply, as well as the ink and paper you use.

To start, I wrote with both nibs without applying pressure to flex the tines. This is how you would normally write with any fountain pen. Using a pair of digital calipers and a magnifying glass, I measured both lines to be the same at 0.3mm.

Then, I flexed both nibs in a figure-eight pattern. Pressing on the downstroke spreads the tines, yielding a thicker line. Remember, I'm only pushing both nibs as far as I think they can handle without splaying the tines. I measured the thickest part of the line at 0.75mm for both nibs.

How much pressure to flex?

One of the key differences is how much hand pressure is needed to produce the line variation. To measure the amount of weight I used to flex the tines, I placed a piece of paper on top of a small scale we use for weighing packages. I pressed each nib to flex the tines to their full capability.

While this isn't the most precise measurement, it does indicate a difference in the amount of weight needed to activate each nib's flexibility. From my findings, it appears the steel leonardo flex nib requires 50% more force to flex than the 14kt gold.

Flex nib snapback

Another important characteristic of leonardo elastic nib is snapback. This refers to how quickly the tines return to their original alignment after pressure is relieved on the nib. Looking at the bottom of the figure 8 loops, the lines in both the steel and 14kt gold elastic nibs appear to return to their original width at the same midpoint in the loop.

Does the ink flow keep up?

A major concern for flex nib writers is whether the feed will keep up with the flex. One might think that the Momento Zero Grande's ebonite feed would have a major advantage and that the plastic feed of the steel nib would struggle. Over a week of writing with both nibs, I found neither pen to have ink starvation or railroading issues.

The feeds on both pens were able to keep up nicely, even with more demanding, rigorous flexing. The only difference I found was that the ebonite feed had a slightly richer flow. That's why, despite containing the same ink, the Grande with the 14kt gold nib appears to write darker than the Momento Zero with the steel nib.

Nib feedback

In terms of feedback, the 14kt gold nib has a smoother feel on paper than the stainless steel. While I wouldn't say the steel is "scratchy," it isn't as smooth of a ride as the gold nib. Generally, this is what you might expect when comparing Jowo's steel nibs to their gold counterparts. This difference in writing feel is the prime reason why you would consider spending more on the gold nib.