My reviews are about vintage pens I've been collecting for many years. So, please don't expect you can rush to the store or go online to find that particular pen I'm talking about immediately. Also, vintage pens will always be an adventure and in my opinion that's part of the fascination. Even if you find the same model, there's no guaranty that it will behave the same way as described here.
Kaweco as a brand name has made an amazing renaissance in the past several years since the original company went belly up some time in the 1980s presumably. Due to the efforts of H & M Gutberlet, several model names and the brand name have been resurrected but I believe that most FP users never got in touch with the original versions of a Kaweco Dia or Kaweco Sport to name only two of their most prominent model lines. So, here comes a short review of one of the ancestors, a Kaweco Dia 85.
The model name "Dia" was introduced in 1934 to point to the clear ink window that became possible due to the new piston filling mechanism. Before the Dia, the Kaweco pens were safety, lever, or button fillers. Since then there have been numerous versions of the Dia and even models sharing the same model number can have different designs. The model I'm presenting here is a Dia 85 with FK ("fein/Kugel") nib. It also has a "101" imprinted on the barrel and I have no idea what that refers to. In fact, I have a second Dia 85 with M nib that is almost identical except for the position of the two narrow cap bands. This second Dia 85 has a "52" imprinted on the barrel. But now for the actual review.
The outer values (design):
This Kaweco Dia 85 was presumably produced roughly between 1946 and 1954 and is a typical representative of the German elegant black piston filler of the era. Anything colourful would have been considered extravagant or frivolous! It measures 125 mm capped, 117 mm uncapped, and 142 mm posted, quite a typical size for the period. The barrel is indeed slightly barrel-shaped with conical domes at both ends and with a short section, which is 9.2 mm at its thinnest (near the nib). The widest girth of the barrel is 11.8 mm right behind the ink window and the cap's girth is 13.2 mm.
The piston knob is hidden by a blind cap and the piston mechanism is screwed into the barrel such that there is a 7 mm wide section of the barrel belonging to the piston housing. The imprints of the model number "85" and the nib type "FK" are on this visible ring, which is kind of a design element. To make it visible, the edges of the piston housing are very slightly knurled. There is another imprint on the barrel reading "Kaweco-Dia" which once had been gold but the paint is partially rubbed off. I probably should mention that this is a very well-used pen, a real daily worker. The ink window used to be green but has darkened almost completely, which is very common with these pens and presumably due to the use of iron gall inks over many years.
The cap sports two narrow gold plated cap bands, a decorated clip with the "Kaweco" brand name, and an intricate inlaid gold plated finial in the cap screw. Both cap screw and blind cap are knurled and have a conical domed end. The cap also has two breather holes as typical for the era. The pen only weights 15.9 g and this light weight is due to the entire pen being made of celluloid with very few metal components.
Finally, the pen is fitted with a 14k semi-flex gold nib with the imprint of the KAWECO logo together with "WARRANTED" and "14c-585".
The inner values (technical stuff):
The patented screw-in piston mechanism consists of the housing with a square inner boring, the piston rod with a square outer shape, a cork ring as seal held by a plug, which is fixed by a metal pin through the piston rod, the piston spiral inside the housing, and the knob attached to the spiral with another metal pin. The mechanism is rather simple but well-made and functional. It has been used with only minor modifications by Kaweco well into the 1960s. Expect that the cork seal has to be replaced after roughly 70 years! I did it for this one and recommend to be extremely careful or send it to an expert. Due to the construction, you can easily crack the barrel end when trying to unscrew the piston housing or crack the piston rod when knocking out the pin holding the plug of the cork seal. Anyway, with a good, working piston seal in place, the filling works flawlessly and probably will so for the next 50 or so years. If the old seal still works (sometimes after extensive soaking), I recommend to keep it wet all the time to prevent it from shrinking. By the way, the measured ink capacity is roughly 1.0 ml.
Performance and balance:
If you're not used to vintage pens of this kind, it might appear at first like you have nothing in your hand because it's so light-weight. It's also quite small compared to many modern pens. But once you get the knack of it, it's awesome. It's no different with this Kaweco Dia 85. In fact, it has the almost perfect balance for me, both unposted as well as posted. But I usually don't like to post my pens. When writing, my forefinger might rest on the threads but this doesn't irritate me. I don't feel the threads because I have a very light grip, maybe a result of writing with vintage pens all the time. So, the balance is nearly perfect, what about the writing performance? I'd say as close to perfect as it gets. Writing with this pen is completely effortless. The ink simply flows and even won't make a mess on crappy paper, though it is a medium wet nib (and feed) when compared to other pens of the era. There are no hard starts and no skipping and absolutely no pressure is required. This means that I can write for hours with this pen without the slightest sign of fatigue. I also can write very fast without any problems. And I won't need to worry when taking a thinking break because even without capping the pen for extended periods, it will start writing without any problems.
The nib iteself I'd call semi-flex. It won't flex when used in normal or fast writing mode but you can flex it moderately if you want and it will give some line variation (maybe 2-3x). But it's quite clear that this nib was not meant for flex writing. However, the springiness of the nib results in a very nice writing feel together with the smooth tipping that gives just the right amount of feedback even on very slick paper like Clairefontaine or Rhodia. So, it is a little toothier than many modern pens with highly polished nibs (and all the problems that come with this). It's probably comparable to many Aurora nibs regarding feedback. On non-absorbent paper, the nib puts down a truely fine line when not flexed. The "Kugel", meaning sperical, tipping assures that the line has the same width in every direction. It was meant for people who cannot control the "rolling" of the pen and was a specialty nib in the era. The typical German nib till at least the 1960s was more chisel shaped what might be called a stub or cursive italic today. Anyway, the FK nib certainly would be a good choice for a beginner because it's very forgiving.
Note: The top pen is the one I just restored and described here with the FK nib. The bottom pen is the mentioned second Dia 85 with M nib, which is not restored yet. I only repaired the badly bent nib so that it would write again.
This is an absolute keeper, a very well balanced pen with an excellent nib and flawless filling mechanism. The design is rather understated but shows a lot of love for details if you are willing to look for them. Despite its age, it is an excellent EDC pen and I use this or similar pens all the time, these pens were meant to be used.