

Pen Class: Intermediate ($26 to $100)
MSRP: $60.00
Street Price:: $50.00
Body Material: Plastic
Nib Material: Steel
Nib Size: EF, F, M and Broad
Cap Type: Screw On/Off
Post-able: Yes
Filling Mechanism: Piston
Ink Capacity: 1.5 ml / 0.051 oz
Overall Weight: 27 g / 0.953 oz
Cap Weight: 14 g / 0.494 oz
Body Weight: 13 g / 0.459 oz
Overall Length Capped: 142 mm / 5.59 in
Overall Length Posted: 175 mm / 6.89 in
Body Length (not including nib): 111 mm / 4.37 in
Nib Length: 19 mm / 0.75 in
Body Length (including nib): 130 mm / 5.12 in
Cap Diameter w/o Clip: 15 mm / 0.59 in
Cap Diameter w/Clip: 18.5 mm / 0.73 in
Cap Length: 60 mm / 2.36 in
Body Diameter at Ink Window: 13 mm / 0.51 in
Body Diameter at Blind Cap End: 11.5 mm / 0.45 in
If this pen were a movie, it would be…
Diamond Stud (1969)

Dan: 8 - The packaging for the TWSBI Diamond 540 fountain pen is absolutely fantastic! I’m so glad TWSBI came up with a packaging method other than just a box wrapped around a clam-shell case. So much thought and material went into the packaging that I don’t know how they’re selling this pen for $50 and making a profit. Their packaging is very Applesque in that it proudly displays the product under a clear case and I especially love that pen is perched atop two pedestals instead of nestled down inside of a box like most others.
I like to keep the boxes to most of my pens and while the small size of the TWSBI box may not give the same experience when initially opening it compared to something like the Delta Dolcevita, its size is more appreciated when having to store it. But, this case looks so good you may not even want to store and instead use it as a pen rest. That’s how good it looks. It’s not just pretty either. Under the white base is a compartment for the wrench and a small container of lubricant. I can’t count the number of times I “ooh’d” and “awww’d” while opening the packaging and discovering all the cool little bits of awesomeness inside. Hopefully, you won’t have to be a manufacturing engineer to understand and appreciate what I’m talking about.
Eric: 7 - Yes, that’s it exactly, Dan, the packaging is very Applesque. If Apple were to sell pens, this is the packaging they would use. It’s not huge and it’s not wood and it’s by no means plush, so it’s not the same experience as, say, the Visconti Declaration of Independence packaging. But it stands so far apart from the usual pen packaging and is done with quality material and such attention to detail that yes, you’ll actually ooh and aah.
If a pen’s packaging is not going to include wood and/or leather, then the TWSBI Diamond 540 packaging is absolutely as good as it’s going to get. Great job, TWSBI.

Dan: 9.5 - The piston in the TWSBI Diamond 540 works just as well and is just as smooth as any other piston I’ve used. I think it’s probably also the easiest to operate as it requires very little effort. I don’t think I’ve ever had the piston stick after being left to sit for any length of time either.
One thing I really like about this pen is the integration with the TWSBI Diamond Ink Bottle. I talk a lot about how I don’t like propriety filling systems, and it doesn’t get any more proprietary than this. But, the usefulness of this system more than makes up for its limitations, which really aren’t all that limiting. The TWSBI adapter can be removed from the bottle so any pen can fill from the bottle.
Eric: 7.75 - No doubt about it, the TWSBI Diamond 540 has an excellent piston filling system. It’s not the absolute best piston I’ve used, but it certainly holds it’s own and has nothing to be ashamed of, especially considering the 540′s price point. When I use the 540′s piston, I get the feeling that it requires more turning than other pistons to go from one extreme to the other. This may be true, owing to the large ink chamber of the pen, it may be an illusion owing to the fact that the pen is a demonstrator and I watch the piston’s movement from start to finish.
As for the TWSBI Diamond Ink Bottle, I’m afraid I just have no use for it. It’s a nice bottle and I understand why some might like it, but I don’t have any complaints about putting my pen’s nib and a bit of the section into a standard bottle for filling and then cleaning up a little afterward. I actually like it if a little ink remains on the nib. And I can’t see myself moving ink from the perfectly good bottle in which it came to the TWSBI bottle and then having to remove the pen’s section for the best filling experience. Sure it’s different, sure it’s cool, but I’ll pass.

Dan: 8.75 - My test drive with the Diamond 540 was incredible. I filled it using the adapter on the bottle but then realized I couldn’t start writing until the feed was primed. Waiting for the feed to prime after the first fill is the only downside I can see to using the proprietary filling system. So, since I have zero patience I emptied the pen and filled it without the adapter, just like any other fountain pen. That went smooth and now I was ready to write.
The Broad nib that I ordered is very smooth and the ink flow suites me perfectly. I didn’t experience any hard starts or skipping whatsoever. I did notice a tiny amount of flex from the steel nib but just to the point where it’s more than being a soft nib but less than semi-flex.
Eric: 8 - The most difficult part of this Test Drive was deciding which color ink to use in the pen. After much debate, I finally opted for Waterman South Sea Blue. The pen filled just as it should have and after one quick swipe with a Kleenex, I was ready to take it for a spin.
No hard starts? Check. No hesitations? Check. No skipping? Check. Comfort? Check-check. Smooth nib? Weelll… yes, as smooth as you can expect from an over-the-counter fine nib made of steel. The flow seemed a tad dry, but I’m going to blame that on the fact that I opted for the fine nib.
I also noticed a little flex in the nib, Dan, but I’d probably describe it as a little spring. The nib is not a nail, that’s for sure, but coaxing obvious line width variation from my fine nib requires more pressure than I like to use.

Dan: 7.25 - The steel nib of the TWSBI Diamond 540 is very nice, even though it appears to be a bit small, but that’s probably just me. The imprint is deep and crisp making it very easy to see the TWSBI logo, the word “TWSBI” under the logo, and the scroll work along the tines. I also like that the size of the nib is marked just to the left of the word “TWSBI”.
If you make a habit of adjusting the flow on your pen or like to grind your own nibs then you’ll appreciate that the nib and feed on the 540 simply pull out of the section as two separate pieces. The plastic feed does a great job of controlling the flow and keeping it consistent.
Eric: 6.75 - A score here of 7 is probably the most I could give a steel nib, and the TWSBI nib would have received a 7 were it not for the scrollwork that looks more like an afterthought than a well-planned design. Other than that, this is a top-notch steel nib. The stamped TWSBI logo looks terrific, as does the name TWSBI just underneath the logo. The nib size marking is less sharp, but it’s nice to have for future reference. The feed caught my attention because under a 10x loupe, it makes me think I’m looking at a wonderfully angled, black-balconied highrise hotel somewhere in Dubai. Not that I’ve ever been to Dubai, but hey – I’ve seen pictures.

Dan: 7.25 - I mentioned earlier that nib seemed to have more flex than being called soft but not enough to be a semi-flex nib. After experimenting with it a bit in the Road Trip I would say that’s still accurate but it’s much closer to a semi-flex than I first thought. I ordered the Broad nib and was able to flex it to twice its width with reasonable effort. I still wouldn’t call it a semi-flex nib, but you can certainly add a little line variation to your writing with this nib. To be clear, don’t buy this pen because of whatever amount of flex you think it may have.
Eric: 7.5 - The pen performs very nicely, indeed. It never complains, never skips, never takes vacations and is always ready for more. The dry-ish flow that I noted during the Test Drive did not translate to any sort of problem. The pen all but laughed at me when I tried to write faster than the ink would flow. This pen also supplies the single most important performance attribute: Zero Frustration.

Dan: 8.25 - You can take one look at the Diamond 540 and see that it’s pretty but when you really get up close you can start to see that a lot of time was spent on the design of this pen. The diamond shaped facets on the body give the pen a unique look and feel. I don’t think I’ve seen a fountain pen shaped quite like this before. The cap was designed to seal tightly to prevent the feed from drying out or ink from leaking due to temperature or pressure changes. Not to mention that anyone can easily take this pen completely apart and put it back together. You don’t see manufacturers give you the instructions and the tools to do that. It’s very apparent that the Diamond 540 was designed with a purpose: to be practical, yet beautiful.
TWSBI is well aware of the areas they need to improve. If you’re familiar with the 530 you can probably spot some of the differences in the improved 540. The most noticeable probably being the increased ink capacity. TWSBI also increased the thickness of the twin o-ring piston seals, redesigned the area on the barrel near the section where the o-ring sits to allow for a smoother feel when removing and attaching the cap, and a slight redesign to the clip to ease the tension a bit.
Eric: 8.25 - The TWSBI Diamond 540′s design is both beautiful and well thought out. The metallic TWSBI logo in a sea of red at the cap’s top may not be as recognizable or have as much history as the famous white star, but it’s strikingly attractive in appearance and in its contrast against the clear demonstrator pen. The clip is handsome, well made, has beautiful lines and is in perfect proportions. The cap band is wider than I like, but it’s devoid of gaudy decoration and fits the pen well. The barrel sports elongated facets that are reminiscent of the pen’s namesake; a diamond.
It is equally evident that the pen was designed not just for good looks and function, but also with user serviceability in mind. Other pens do that, yes, but TWSBI takes the idea a step further by including not only enough silicone grease to last a decade but also a wrench designed specifically to remove the pen’s piston. I didn’t notice either of these items in the last white star product I purchased.

Dan: 7.75 - While TWSBI can certainly design things to look pretty they seem to struggle a bit with durability. Either that or TWSBI customers are some of the most vocal customers I’ve ever seen. TWSBI recently had some issues with the section cracking which led them to redesign the injection molding process. The piston unit has also gone through 5 different iterations because of various issues. But, TWSBI listens to their customers and are very active in fixing any problems that arise. That’s why they made the 540 and that there has been 5 different iterations of the piston.
Other than those quality issues, the fit and finish is spectacular; it kind of has to be since it’s a demonstrator. The plastic and metal accents are all polished to a high gloss. The section is really the only part that I can find any evidence of the injection molding process. Well, that and the end of the piston knob. There are no loose of flimsy feeling pieces. Overall, the TWSBI Diamond 540 is an incredible pen for the money.
Eric: 8 - TWSBI certainly pays close attention to detail, starting with the pen’s packaging and continuing to the pen itself. You’re right, Dan, with the exception of the two seams on either side of the section and the small, unpolished dot at the end of the piston turning knob, this pen shines. I would have scored this category very slightly higher had my TWSBI Diamond 540 not come with instructions for the TWSBI Diamond 530. TWSBI verified with me that they did not re-print the instructions since they are identical for both pens. However, because of the problems associated with the 530 (which led to design changes), I’d prefer to have instructions indicating that my pen is what the cap band proclaims it to be; a 540.

Dan: 7.5 - The first thing I noticed during the Road Trip was how heavy the cap is when posted. I bet Eric won’t be able to stand it for more than a few seconds. But I was fine with it after a few minutes as I normally write with the cap posted. The polished body and section sure look nice but become slick when my hand started to sweat, but no more than any other fountain pen I’ve used. The overall size and weight of the pen felt very good in my hand and I only started to notice a hint of fatigue as I approached the 20 minute mark. The nib and the feed work very well together and never left me wishing for more.
Eric: 7 - The TWSBI Diamond 540 is certainly a get-the-job-done workhorse type of pen. I think it is especially suited to note taking, whether in the boardroom or the classroom.
You are correct, Dan, I tried to start the Road Trip with the cap posted and I couldn’t even leave the driveway. Talk about a heavy cap! I could find absolutely no balance with the pen posted and removed the cap before I had written the fifth word. Once free of the top-heavy load, the pen completed the 21 Minute Road Trip in a dignified manner. I noticed early on that the pen’s comfort leaves a little to be desired, but never did the pen skip, hesitate or even threaten a hard start. I cannot call the Road Trip an amazingly wonderful experience, but I can’t complain much either. Except for the hint of hand discomfort after five or six minutes of non-stop use, the pen proved quite capable of taking you where you need to go.

Pros:
- Best value fountain pen on the market
- Ease of dis-assembly
- Customer service
Cons:
- Only available as a demonstrator (as of January 18, 2012 – but soon to change).
- The jury is still out on whether durability issues have been resolved.
Famous Last Words:
Dan: If you do any research on the TWSBI Diamond 540 you’ll probably see some of the issues that people have had with their pens. But, don’t let that deter you from buying this pen. TWSBI has the best customer service I’ve ever seen from any company in any industry. If you have a problem they will fix it, and usually free of charge. Bottom line: this pen needs to be in your collection.
Eric: After my lackluster experience with the TWSBI Diamond 530, I did not expect to fall in love with the TWSBI Diamond 540. But oh yes, this pen is staying in my daily carry case.
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