Until now, I've had no real need to swap out nibs, and the only nibs I've removed were from the Noodler's Ahab, Lamy Safari and a a Jinhao 188... so nothing really difficult. I know some pens are harder than others, some are just a no-go... pen in question right now is a cheap Chinese Duke, the Uranus 620 (Fat Man Atomic Bomb WWII) pen... honestly, seen so many variations of the name I have no idea what the 'official' name is. Saw it today while browsing on eBay and absolutely loved look how it looks. Downside is... the F nib with zero flex. From what I've read/seen online, it's a nail-like sharp nib. Not worried so much about flex, but, if I could, I would love to grab an M nib for it. Anyone know much about these pens? How they come apart and if the nib can be swapped out? I haven't ordered one yet, but honestly, if I have to I'll order a 2nd Duke pen with an M nib as a donor for this pen, or, if I'm lucky, buy a nib on it's own, like a Jinhao, Goulet or something... I'll buy this pen either way, but for how I write, I hate F nibs. http://i00.i.aliimg.com/wsphoto/v0/1855561086_3/Duke-Uranus-Fat-Man-atomic-Bomb-World-War-II-Cap-Fountain-Pen-D22.jpg