TWSBI Diamond 580

I managed to snag the TWSBI 580 on eBay back in December of 2015. I won it on a Friday evening and it wasn’t delivered until the following Monday/Tuesday. It was a pen that I had found myself very excited for and to this day remains as one of my most pleasant new pen days. I wasn’t home when the postman delivered the package, but he got a neighbour to sign for it and left the parcel in my designated safe place. Almost as though it was foretold in the stars that this was a pen that needed to be in my collection – as it still sees regular rotation even in July 2017, over a year and a half since we first met.

TWSBI Diamond 580 fountain pen review
TWSBI Diamond 580 inked with Kaweco Blue Paradise

I got into the pen community in October of 2015, so it was only a month after my first pen purchase (minus a few Chinese pens I had ordered) since really diving into the hobby. There are many things that made me giddy about this purchase. For starters, it was my first broad nib and all the other pens I had ordered were standard mediums. It was also my first piston filled pen and my first demonstrator. It was a many of firsts for me.

  • Price: £46.99
  • Recommend: Absolutely – This pen remains in my regular rotation after a year and a half. It’s a nice medium-range priced pen and the demonstrator nature is a cool feature.


The most obvious thing about the pen is that it’s transparent. This means that you can see the inner workings of the pen as well as the ink sloshing around in the barrel (if you have ink in it.. Of course!) which I think is not only a super awesome thing, but also a super useful thing because it means you can see if there’s something wrong with the inside of the pen without having to disassemble it entirely. However, if you wish to disassemble it then you are provided with a wrench by TWSBI to unscrew the piston unit (as well as some silicon grease).

TWSBI Diamond 580 fountain pen review

The barrel is plastic. In the past, TWSBI pens have been criticised as being prone to breaking. The 580 serves as an upgrade to the 540 – an earlier TWSBI model that had cracking issues. TWSBI went even further with this in the aluminium [580-AL] model which is said to add even more support to the pen. I’ve never had problems with cracking, but their customer service is raved about on social media, so I shouldn’t worry about having long term problems. I can attest to this after having to request a new Eco barrel after using KWZ ink, which was my own fault as I felt adventurous.

The cap is a screw-type with the TWSBI logo on the finial in a red background. The clip is usable but feels a little too easy to use; I would be very careful when using it. The rest of the cap is transparent, other than the inner cap which is a smokey grey colour. Pilot does the same thing with this smokey inner cap – I still don’t understand what possesses them to make this decision as it really does affect the look of the pen in my opinion. Have a clear inner cap and show off the nib, something that fits with the rest of the whole pen!

TWSBI 580 fountain pen review
Smokey inner cap (that needs cleaning apparently, whoops)



And speaking of the nib, it is a stainless steel JoWo nib. Something rather handy is that you can order replacement TWSBI nibs that will screw straight into your pen (they come as whole units) from your favourite retailers that carry TWSBI pens and it means that you can get different nib grades (or replace a damaged nib). Alternatively, you could go to FP (no affiliation) and get yourself a gold nib, if you feel yourself so inclined. The nib that I have on this pen, as I mentioned above, is a broad. I think it’s a respectable grade, and below I have compared it to a Pilot Custom 823 of the same size. I don’t notice any skipping or hard starts – the flow is very good, which keeps up well with fast writing, and it’s a wet nib (which I love!) For those who enjoy reverse writing, the nib is taken down to a respectable fine, but the performance of the nib isn’t sacrificed as I still find it wet.

TWSBI Diamond 580 fountain pen review handwritten
Written on Fabriano 90gsm paper
TWSBI Diamond 580 fountain pen review Pilot Custom 823 broad
For comparison purposes I tried not to use ‘too’ much pressure with the 823 because it’s gold nib and a bit bouncy


The TWSBI 580 is a very nice size, but perhaps a little on the light side. It’s larger than the  M800 but the same size as the Pilot Custom 823; two pens that I think are the ultimate pens. You have a pen that’s very well balanced, but you can’t really feel much of that balance. The model that I am reviewing is the 580, but there is a version that uses more aluminium and as a result gives you a heavier pen. TWSBI also offer these in a variety of colours, but I think it’s a little gimmicky and not the biggest fan of these different colours so I’m happy with my regular one. Each to their own!

If posting is something that’s important to you then I’d recommend the TWSBI Mini, because posting gives you an incredibly large pen, as well as a very unbalanced one. The cap also doesn’t post deeply either which makes it feel unstable. Furthermore, when posting you run the risk of potentially turning the piston (I’m not sure how the TWSBI Mini mitigates this). For this reason, I wouldn’t say that this pen is a postable pen, but I did include the posted length at the bottom of the post with the measurements as it might prove useful to someone.

Quite a few size comparisons below:

TWSBI Diamond 580 fountain pen review Pelikan M80 Souveran Pilot Custom 823
Left to right: Pilot Custom 823, TWSBI Diamond 580, Pelikan Souverän M800
TWSBI Diamond 580 fountain pen review Pelikan M80 Souveran Pilot Custom 823
Left to right: Pilot Custom 823, TWSBI Diamond 580, Pelikan Souverän M800
TWSBI Diamond 580 fountain pen review Pelikan Platinum #3776
Left to right: Platinum #3776, TWSBI Eco, TWSBI Diamond 580, Pilot Custom 74, Pelikan Souverän M620 Piccadilly Circus
TWSBI Diamond 580 fountain pen review Pelikan Platinum #3776
Left to right: Platinum #3776, TWSBI Eco, TWSBI 580, Pilot Custom 74, Pelikan Souverän M620 Piccadilly Circus



All of TWSBI’s pens fill from bottled ink – you cannot use a cartridge or converter. All are piston fillers, with the exception of the Vac 700(R) and the Vac Mini. To fill, you submerge the nib into the bottle of ink and turn the piston knob to suck the ink up. It works on the same principle as a converter, so you have to extend the plunger all the way to the bottom to suck it up. The great thing with a piston is that it increases your ink capacity. It does add to the cleaning time, but thankfully you can disassemble TWSBI pens to make the cleaning process a little bit easier.

To fill the pen you could also get a TWSBI Diamond ink bottle which apparently makes filling the pen is easier (even though it isn’t difficult in the first place). I think these things provide more of a gimmick value than being something of utility. Though, I’ll put up my hands and admit that I’ve never used one.

TWSBI 580 AL fountain pen review

Be careful when lending your pen to others, however. I have found that, for whatever reason, people are instantly drawn to the piston and decide to twist it, which results in ink being released from the nib.

Other options

The 580 occupies a nice niche in the pen market. It isn’t exactly a starter pen, but it isn’t approaching the £100 mark. The Platinum PTL-5000 is a good bet, and is actually a gold nib pen. It’s slim, so I would recommend this if you’re basing your decision off of a budget.

Other TWSBI pens that might intrigue you would be the Eco, which is a cheaper pen with a few aesthetic differences – in a word I would say more “streamline”. Of course, the aluminium version is an option for a little bit extra on top (~£10). Though if you’re looking to spend even more, you can get a Vac 700R for £20 more. If size is an issue then you might want to consider the TWSBI Mini which also allows you to post.

However, if you’ve got an expandable budget then I would recommend the Pilot Custom 823 or Pelikan M800 as I mentioned above, which are around the same size but heavier. Of course, on the flip side of this, if it’s just weight you’re looking for then go for the 580-AL and you might find your favourite colour! Be careful though, there are many colours that have been released in the past and are now discontinued, which can lead you down a rabbit hole…… You have been warned!

And finally…

I am glad that I got the TWSBI 580, which is evident by the fact that I still have it in regular rotation. Watching the ink slosh around and by viewing the workings inside, while not a mechanic or engineer myself, still does intrigue me and also serves as a nice talking point. The larger ink capacity does prove useful as well – especially with this wet broad nib. It doesn’t drink through ink, but a larger capacity certainly helps. But as a result I do not resent cleaning it out as it is fairly easy. Though, I don’t always completely disassemble it and I would advise against doing so every time, but it’s okay to unscrew the nib from the section, for example. All in all, a good pen and highly recommended!


  • Demonstrator so you can see the ink and inner workings
  • Reasonably priced
  • Brand provides great customer service
  • Replaceable nib units
  • Well sized


  • Pens have been known to crack in the past
  • Cannot be posted (if that’s something that’s important to you)


  • Weight cap: 14g
  • Weight body: 14g
  • Total weight: 28g
  • Length capped: 14.1cm
  • Length uncapped: 13.0cm
  • Length posted: 17.6cm

Writing sample on Fabriano 90gsm paper with Kaweco Paradise Blue, the nib is broad

TWSBI Diamond 580 fountain pen review sample handwritingTWSBI Diamond 580 fountain pen review sample handwriting

One thought on “TWSBI Diamond 580

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s