I googled “Osmiroid 75” and discovered that one of my favorite flex nib artists wrote about his Osmiroid sketch pen on the Fountain Pen Network. It’s good to know that someone seems to like this unusual nib as much as I do, albeit he did write his review 5 years ago. (Antoniosz, if you’re reading this, do you still have that pen?) That review also has a very informative scanned image of the nib options available for the Osmiroid 65 and 75.
The Osmiroid 75 is a piston filler. The nib screws out, just like Pelikan and Esterbrook nibs.
At first, I thought the tip of the nib had worn down; and then I realized it was really this almost-stub. An large overfeed helps keep the tip supplied with ink. There is also a slit on either side of the rectangular cut-out in the middle of the nib, which reminds me of slits cut in steel nibs to make them more flexible. The feed is an unusual configuration as well.
My pen has a tiny crack near the ink window, which I hope to be able to seal. So far, though, it hasn’t been a problem.
Note the slight parting of the tines. Because of the shape of the nib, though, this slight spread makes for a wide line.
It’s a sweet nib for both writing and sketching.
I used Noodler’s Golden Brown in it before Noir Diamant, in an earlier sketch. The variety of lines that can be achieved by both changing the angle of the nib to the paper and the pressure is quite pleasing.
If you’re into fountain pens more for the result rather than the pen hoarding part of the hobby, you can’t do much better than a pen like this.