TWSBI Mini Classic fountain pen

Model Mini Classic
Nib Material Steel
Nib Sizes EF,F,M,B
Filling System Piston
Dimensions Capped Length: 117.5mm / 4.6″
Posted Length: 140mm / 5.5″
Uncapped Length: 108mm / 4.25″
Barrel Diameter: 13mm / .51″
Section Diameter: 9.7-11.3mm / .38-.44″
Weight 21g / 0.74oz
Notes Available in 3 styles: Classic, Black, and Clear
Price $50
Availability Now

The TWSBI Mini, it’s finally here! It feels like we’ve waited ages for this pen to arrive. We first reported on it just over a year ago and in December we announced an estimated release date of June 2012 on our TWSBI Timeline. Since that time the Mini has stayed under the radar, only surfacing to show off possible color options. On October 22nd they officially went on sale in three styles: an all clear demo, solid black with chrome trim, and the Classic, which combines a clear barrel with a black cap, section, and piston knob.

Being in the Diamond family, it’s not surprising that the Mini looks like a shrunken down 540. There are a couple slight differences in the Mini that I actually wouldn’t mind seeing on the 540. The biggest change, and a vital one for the Mini, is the addition of threads to the rear of the barrel for posting the cap. The other is the style of the cap band. I’m glad TWSBI didn’t just transfer the 540’s over the Mini as that would have looked odd. In addition to those two changes there’s also the addition of a metal accent at the front of the section and the seals on the piston of the Mini look ever so slightly thicker than on my 540.

The Classic called out to me the most and I sincerely hope TWSBI offers the 540 in this style. Even though the changes to the Mini were few and subtle, I think it looks much cleaner than the 540. The revised cap band definitely contributes to this new clean look, but I think most of it comes from the mixing of opaque black and clear parts. The black piston knob, section, and cap cover up the bits we’re used to seeing, creating a semi-professional look while the clear barrel reveals the piston, adding some uniqueness and intrigue to what would be an otherwise boring pen (glances at the all black Mini). The only issue I have with the Mini is the o-ring on the rear of the barrel. It’s a useful feature and I’m glad it’s there, but it detracts from the pleasing lines of the pen.

Owning a TWSBI that was designed to be posted is like a dream come true. The cap locks down securely in just more than one full revolution and engages the o-ring for the last half a turn. As long as the cap is touching the o-ring it’ll stay in place. That half a turn also gives you enough play that you should easily be able to find a spot where the clip lines up with the nib. That’s important because when the cap is fully locked down it doesn’t line up with the nib. Some of you may not care about that, but for me it’s one of the most important aspects of a pen. So, while the o-ring may not be the most beautiful part of the pen, it is certainly one of the most useful.
TWSBI Mini fountain pen uncapped
The TWSBI Diamond Mini is a convenient and comfortable pen. I think it offers the best of worlds. The most likely competitor to the Mini is probably the Kaweco Sport. While the Kaweco is much lighter and more compact, it’s not nearly as comfortable to use. It’s also not a piston filler. But, it is half the price and has lots of nibs that are easily swappable, readily available, and cheaper than nibs for the 540 (note: the 540 section won’t swap directly onto the Mini, but the nib/feed unit will). To determine which pen is for you really depends on how light and compact you need your pen to be. For my use, which only requires a pen to be compact enough to hide in a shirt pocket, the Mini is perfect.

The piston unit in the Mini is solid. The dual seals are thick and beefy and should last a lifetime. The piston is well designed in that it fully retracts, butting up against the unit housing so that as much of the barrel can be filled as possible. I did run into a bit of an odd feeling while operating the piston. On both of my Minis I noticed that the action wasn’t completely smooth. There are three points during the extending/retracting cycle where it feels like the piston knob is settling into place, like there’s detents along the shaft. I don’t know if this is found on every Mini or just mine. I’m guessing this will smooth out with use. It’s just odd because I never noticed it on any of my 530/540’s.

I’m happy to share that the Mini is fully compatible with the Diamond Ink bottle. Filling is quick, simple, and clean and it all but guarantees a 100% fill.

Daily use of the Mini has been quite pleasant. It nestles nicely into my shirt pocket and is light enough that most times I forget it’s there. When it’s needed, the pen can be used to make quick notes without posting, something the Kaweco Sport couldn’t do, at least not without being annoyingly awkward. For more extended writing sessions the Mini is just large enough to be comfortable, that is until things start stretching into 3-4 pages. When the writing is done the Mini easily clips back into my shirt pocket with one hand.

I received a fine and a broad nib in my pens and they both performed wonderfully out of the box. I hate to say this, but I was actually surprised by how well they wrote given TWSBI’s history. Both nibs were smooth and the flow in the broad nib was slightly wet while the flow in the fine nib was spot on in the middle of the range. Hopefully, this is a sign of things to come. But if it’s not, I wouldn’t use it as an excuse to not buy a pen. If you like it, buy it, and if the nib is bad then send it to a nib meister to be perfected. It’s worth it.

TWSBI has done a lot of things right with the Mini. It’s an excellent fountain pen regardless of size or price. It’s very easily user serviceable and comes with excellent customer service. There are a few other options out there that do the whole compact thing better than the Mini, but none that are as well rounded.

This pen was provided for review by TWSBI.

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  • Ira Stone

    couldn’t agree more. Great review.

  • pelahale

    nice job again Dan. Where the hell’s Eric? Is he in trouble or ill?

    • Dan Smith

      On holiday.

  • GTown_Dave

    Thanks for another fine review. Appears to confirm everything I would
    have expected from this eagerly anticipated TWSBI offering. I hope to
    pick up one or two for myself in the near future.

    Speaking of long awaited, will TWSBI *ever* be releasing the Vac 700 in a
    clear demo version? I feel like it was mentioned more than once, only
    to have since fairly disappeared from the face of web speculation.

    • Dan Smith

      Regarding the clear Vac700, I think people have stopped commenting about it because TWSBI said it’s coming and there’s not much else to talk about. Retailers might get two weeks notice, but we won’t know for sure until we can click the “Buy” button.

  • Azizah Asgarali

    Nice. Great pics too. You of course covered everything I was curious about! At first I was thinking I could survive without one but… sigh… I don’t think that is the case anymore. Plus, I love mini things!

    • mjcong

      hahah seriously agree with the pen gourmet here.. i thought i could survive without one.. *off to goulet pens to look* and *waits patiently for them to be back in stock*

      • Dan Smith

        It looks as though still has them all in stock except for the Classic in EF, and F. is also an option if you’re looking to support a retailer.

  • Ivan Romero

    Awesome pics as always. I am not sure if I want this one. I had a lukewarm feeling about it when it was announced. It’s not bad looking. I think I want to wait for the metal TWSBI.

  • Ron Gilmour

    Couldn’t agree more. This is a fantastic pen. Huge props to TWSBI for making it and to FPGeeks for a great review.

  • Peninkcillin

    Hope it comes with the italic nib.

  • breck

    Bless you Dan for giving section diameter! Thank you!

  • Freddy

    I, too, was amazingly pleased with the Fine nib on my demonstrator Mini. The Fine nib that came on my 540 is also superb. Both wrote beautifully right out of the box. However, my Vac 700 nib has been nothing but trouble and that was after it had been replaced once. (TWSBI’s customer service is excellent, by the way.) So it has been a real hit-or-miss when it comes to the nibs. As you stated, Dan, hopefully the nibs on the Mini, or ones as good, are in TWSBI’s future pens.

  • The Ruffled Quill

    Thanks for the review – if they would reverse some of the design “improvements” back to the 540 it would be great. On the Vac 700 I too found the nib troublesome and unlike the 540 nib options are limited – so I installed a Monteverde stub nib instead and my Vac 700 is now a great writer and is constantly in my rotation…

  • Flub de Rabbit

    You’ve hit the nail on the head; a great emergency stand-by for when your main pen runs out of ink, small enough to carry unobtrusively, and just about big enough to write a couple of pages with. The posting mechanism works well – wouldn’t it be great to see this on the next iteration of the Diamond? It is a ‘mini’ so don’t expect to write for reams and reams comfortably; it’s a bit too small, and too light, for that. The nib also isn’t quite as satisfyingly srpingy as that on the Diamond. But, it looks good and is decent value for money – TWSBI impresses again.

  • bnroberts

    I’ve been using my Mini (classic, medium nib) for about two weeks now. It’s a gorgeous pen, and feels nice to hold. However, I have two significant problems and will be switching back to my Lamy Safari, at least for primary use.

    The first is writing: my pen skips a LOT, making writing a painful experience, and it’s often not quite ready to write, even after having been capped only for an hour or so.

    The second is that sometimes I notice ink on my hands. Usually it’s just a little bit, but this morning I ended up with quite a bit of ink on multiple fingers. I think what’s happening is that the piston knob gets turned a little bit while in my pants pocket, expelling ink into the cap. That ink then contaminates the exterior or the pen, especially the piston knob when posting. So this second complaint is really more an issue of me using a piston-filler in a way that perhaps it’s not meant to be (i.e. carrying around in jeans front pocket), but it’s a problem for me that I didn’t have with the Safari.

    • Dan Smith

      Sorry to hear about the skipping issue. In general, I’ve heard good things about the performance of the Mini. I’d contact TWSBI and see if you can get the nib unit replaced.

      Regarding the piston issue, I really don’t think it’s turning while in your pocket. I would attribute this to your body heat heating the air in the barrel, expanding, and releasing ink into the cap. I’ve experienced this on almost every pen I’ve carried in my pants pocket.

      • bnroberts

        Yeah, I was wondering if it was body heat (rather than piston knob turning) a well. It’s just weird that this happened early this morning, when then pen hadn’t even been in my pocket for very long, and it was sorta chilly outside, so the pen shouldn’t have been warmer than any other time. But I’ll see if this continues.

        Regarding skipping, I previously ordered a Fine nib set from TWSBI which will hopefully arrive soon. I’m hoping that this new nib will perform better. But I guess it can’t hurt to ask TWSBI if they’ll replace the Medium nib. I’m pretty sure it’s not a paper issue, since the skipping occurs in both my Field Notes (which works great with my other fountain pens) and Moleskine Evernote notebooks (paper not quite as good, but never had skipping issues in this notebook, either).

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  • Breck

    “There are a few other options out there that do the whole compact thing better than the Mini…”. What would those be?

    • Ramón

      That’s the problem of a review promoted by the manufacturer.

      • Dan Smith

        That’s quite the accusation to be throwing around with no supportive statements.

    • Dan Smith

      Off the top of my head, the Kaweco Sport, Liliput, and Caran d’Ache Ecridor XS.

    • Robb Swenson

      Compact pens is a broad statement. Some large pens have narrow sections. Small pens in length can be achieved by leaving the pen unposted. Parker Jotter is very narrow, too narrow for me. There are many vintage smaller pens that can be stellar pens, such as the Parker Slimfold, or even interesting pens like the Parker 180 or Parker Falcon. These are narrow pens. The TWSBI Compact is too short for most to use long unposted, but it is not a narrow pen. It is actually on the large side, in the hand. I am of the opinion that a larger diameter pen is easier, and more relaxing to hold.

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