TWSBI Diamond 540 EF Review

First I have to start off by telling a little story of how the TWSBI Diamond 540 came into my life. I was having a particularly crappy week at work and knew my birthday was coming up so I thought I’d cheer myself up with a new fountain pen so I ordered a TWSBI 540 on the strong recommendations of various podcasts I listen to (I blame you, FPGeeks and Pen Addict!).

twsbi in the house. whatcha gonna do?

The day it arrived I was too busy to play with it until I got home and my husband said he had something he had to do in the office so I needed to “keep myself entertained” for a few minutes after dinner. I took this opportunity to open up my new TWSBI and load it with ink. In walks my husband with a birthday present. Can you guess what it might be? Yep, just as I finished adding ink to my new TWSBI, he walks in with a wrapped box containing a TWSBI 540! Smart man!

make that two! @gouletpens my husband bought me the exact same pen for my birthday!

Since I’d already inked up the TWSBI I bought, I didn’t even break the seal on the one he bought and it is speeding its way back to Goulet Pens in hopes of turning into credit for a future pen purchase (Hello, Namiki Falcon?). Shall I move on to the review now?


The nib is quite lovely on the TWSBI 540 and, to me, the pen is HUGE! Its a weighty, substantial pen with a large ink reservoir and a piston filler mechanism. Filled, I put it on my trusty scale to discover it weighs 29gms capped! That’s heavier than my Lamy Studio in brushed stainless steel. I don’t quite know what makes the TWSBI so heavy being that its a plastic body but there you have it.

I chose the clear demonstrator model so that no matter what ink color I chose, it would not clash with my pen. Silly, I know but I didn’t have any demonstrators so let this be the first! I purchased the EF nib. I write small so I tend to prefer the finer nibs but as you’ll see, the EF is so fine that an F or M nib might be just perfect for someone with larger handwriting.

Cap band

The cap is a twist-off with the company name etched discreetly on the chrome cap.

TWSBI dot on cap

On the cap end is a pretty TWSBI logo jewel in red and metallic silver. Quite pretty and made the pen feel special.

I filled my TWSBI with my favorite ink, de Atramentis Pigeon Blue, in case you’re curious (and you’re reading a pen review so of course you’re curious about the ink, right?). It was a breeze to fill, and was not messy at all. I just jammed it into a bottle of ink up to the edge of the nib and twisted the bottom to fill. It didn’t leak, dribble or in any way soil my hands.

TWSBI 540 writing sample

In writing tests, I was most surprised that the TWSBI 540 wrote smoothly and precisely from the minute I filled it. I have not had to “prime it” at all since I filled it and its been used on and off for over a week. The 540 is a big enough, heavy enough pen that I could not write with the cap posted though if you prefer a big heavy pen, the cap does post snugly.

When compared to a quick writing sample from my Kaweco Sport EF and my Pilot Prera F, you can see that the TWSBI falls in between the two in regards to line thickness and wetness. The Prera is definitely the driest of the three and the Kaweco is the wettest.

TWSBI 540 compared to....

Comparing the size of the pen to my other go-to fountain pens you can see that my pens are progressively getting larger though I still reach for my Kaweco more often than any other pen. I have very small hands and the lightness of the Kawecos tend to not fatigue my hands the way larger, heavier pens do. Alternately, in meetings, I take my 540 because it performs the minute I uncap it and it looks like I mean business. And the large, visible reservoir makes it a great daily carry pen because its easy to tell if you need a refill.

For a really detailed review with more technical information than presented here, I recommend the FPGeeks Awesome Review.

TWSBI Diamond 540 EF purchased from Goulet Pens for $50, as was the de Atramentis Pigeon Blue ink.

(This pen was tested on the Miquelrius medium flexible 300 grid paper book purchased from B+N.)

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