The TWSBI Diamond 540 has been a phenomenally popular pen, and for good reason: it’s the cheapest piston filling fountain pen of decent quality currently available. Well, at least if you know where to look. That problem’s due to TWSBI phasing out the 540 for the new 580 that will bring a few design improvements.

As seen in the image below, there are several noticeable differences between the 540 and 580. The first is the shape of the clip. We’ve already seen this on the Mini and the Micarta. Personally, I prefer the look of the one currently on the 540, but whatever.

One subtle change is the use of thicker o-rings in the piston seal. I haven’t heard of this being an issue so I’m a bit curious as to why the change.
TWSBI 580 540 fountain pens
The other three changes pointed out in the image all strive to resolve cracking issues. There’s now a metal sleeve in the front of the section that the nib unit friction fits into. Previously, there were several ribs around the nib unit designed to help align the unit and the section. A major cause for cracking the section came when people removed the nib unit and tried to reinsert it without lining up those ribs with their intended slots in the section. This new metal sleeve should definitely resolve that.

Looking towards the rear of the pen we can see the metal collar in the the barrel of the 540 has been removed and the piston unit now threads directly into the barrel. Also of note is the metal ring at the rear of 580’s barrel. I don’t know the exact purpose of that ring and my inquiry went unanswered so I’ll have to speculate. Many would be ecstatic, myself included, if this was intended for the cap to post to. It’s a similar design as currently used on the Vac700. But, I don’t think that’s the case. If you post the 540 you’ll see that the cap posts onto the piston knob and the lip of the cap would have to move several millimeters to get to the point where the metal ring is. TWSBI would have had to completely change the dimensions of the rear of the pen, the inside of the cap or both to get this to work. I’d be surprised if TWSBI made such a significant change as Jim (Speedy) has said before that he never intended people to use the pen in the posted position.

One thing’s for certain: I can’t wait to get my hands on one!

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  • Charles Latshaw

    I’ll bet that metal ring in the back is there to prevent cracking, too. My 540 isn’t cracked in the front, but it definitely is cracked right there in the back. Because of those cracks, my entire plunger mechanism can be pulled out without unscrewing anything.

  • snedwos

    As long as the nib units are cross-compatible, I’m happy!

  • The Scribbler

    Any word on colors the 580 will be available in? I hope they bring back some of the 530 colors.

    • snedwos

      green or red, would be my choice. Something like the Mini Classic colour scheme would be great too. And i wish the amber of the vac700 was more like the amber of the 540…

      • Maja

        Yes, green and red would be great! Also, italic nibs in slightly narrower widths (0.7mm & 0.9 mm). Thanks for the information, Dan!

        • Carol1313

          Yes, all of these. The red on the ROC was really lovely. And I always look for .7 and .9’s, but the only loose nibs I’ve found are Nemosines on the x-pens site. Any more choices out there?

          • Qyandri

            I second green, and add the Vac700 blue and a purple to the want list. Also a big supporter of the smaller width italics, but more than anything, I want flexible nibs! I love the nibs and hate the bodies of the Noodler’s Creapers/Konrads/Ahabs.

  • Esteban López Vega

    Now you need to do another giveaway, and me to win it again! ;)

  • tsz shun wong

    Still waiting for the eco version .

  • Chuck Kim

    Must. Have. 580. >_<

  • Speedy Wang

    Metal ring on the back of barrel is for two reasons. one, aesthetic point of view to match the metals in cap. second, help balance the weight of the pen during writing.

  • Nic

    The metal rings unfortunately didn’t help with the cracking on my Mini, so I’m willing to bet its not going to completely solve the cracking problems on the 580 either. Though I have heard much less about the cracking issues on the Mini, so perhaps it will at least help.

  • vhr5

    I don’t own a 540, but I am very interested in purchasing the 580 and eventually the Eco. I would prefer to post the cap, but if that is not an option then oh well. I enjoy using my VAC 700, so I sure I will enjoy the 580 also! I have my credit card in hand, when are they releasing the pen to the public?

  • Lee Smallwood

    I’m not sure I’ll be buying a clear 580 unless perhaps they offer a new nib like a 1.3i. I own a clear 530, a clear mini, and two clear 540s.

    I’d love to see the cyan color brought forward from the 530 line. It and the pink are the only two I didn’t get around to buying, and I don’t really care much about the pink.

    I’m sure they’ll do something with the 580 I will want to buy. Even more than cyan, I’m hoping for a black model.

  • Scribble Monboddo

    I love my 540 and certainly haven’t experienced any of those cracking issues, so I have no complaints other than that the Diamond has been out of production for so long! This re-boot looks just as good and I look forward to trying it.

  • Kevin

    I have a Noodler’s flex Konrad that is piston fill for around $40. It holds a ton of ink and the quality is excellent. I’m not a fan of demonstrators anyway because of the way that the plastic always seems so cheap, so I doubt that I’ll be buying a TWSBI. I’ve heard so many good things about them, but I can’t get past the idea that the pen might crack at any time.

  • Georgy

    I wished they went with the unpolished style for the cap like the Vac 700. It gives a much higher quality feel.