Asvine P36 and nib collar threading

[Paganini]

So, I have this pen, the Asvine P36, which I think folks are fairly familiar with by now. 

(This is a marketing image from the company, not my own photo.) This pen is sold in two varieties, one with an Asvine house nib (which, AFAICT, comes from the same place that Narwhal nibs, Moonman nibs, Hongdian nibs, etc., come from), and the other with a Bock nib. Both the Asvine nibs and the Bock nibs are installed in screw-in nib collars which can be bought separately. (I've sometimes heard these nib + feed + collar combos called "triples.") The Asvine nib unit looks like this, and is (except for the O-ring configuration) identical to the screw-in nib unit in my Narwhal "Nautilus" pen. 

The Bock nib unit is a Bock 250, which can be found in pens from many manufacturers, and looks like this: 

You can see that the two units are not quite identical. In particular, the little protruding thing that the tail of the feed sits in is longer on the Asvine unit than on the Bock unit. It's more difficult to see in the stock photos, but they are also slightly different in length, and their threads begin and end at slightly different points along their length. 

 

My question is, does anyone actually know, from direct experience, (that is, they bought both versions of this pen and examined their interiors) if there is any difference in the pen body itself between the Asvine and Bock version of this pen? I've scoured the internet trying to find the answer, without much luck. 

 

There is a Reddit Man who is constantly posting that the Asvine nib unit is not interchangeable with the Bock nib unit, and that if you want to (e.g.) put in an Ultraflex nib with ebonite feed that FPR sells in Bock 250 nib collars you have to have the Bock version of the pen (which has a $10 - $20 upcharge). 

 

There is a *different* Reddit Man who says that the Asvine nib collars are thread compatible with the Bock nib collars and that the pens are all internally identical. 

 

I bought the P36 with the Asvine house nib. My experience has been that my FPR  Bock 250 nib unit screws in just fine, but then the pen *does not perform very well.* (But maybe that's just because I'm not good at adjusting ultraflex nibs yet). At the same time, my Asvine nib unit fits perfectly into my Narwhal "Nautilus" pen, but the Bock 250 nib unit *DOES NOT.* So I am somewhat confused about just what fits where. I suppose if I have to, I will just suck it up and pay $55 or so for a second P36 with a Bock nib so I can compare them. But I thought maybe someone here had already done this...

[Dan Carmell]

I can’t answer your main question, although I’ve never seen any evidence of any difference between the P36 with either nib unit. I’d recommend asking a reputable seller (like 365Days on AliExpress) since they would know. 

 

I do want to point out that Hongdian makes its own nibs (and pens), per Chinese bloggers. Moonman and Asvine, as I understand, design pens made by others. I’ve heard it said that the three big pen makers are Hero, Jinhao, and Hongdian, with the first two making many of the pens we’ve familiar with under different names. 

[Paganini]

This is not relevant to the main question, but in the interests of not spreading misinformation what I said in passing about my Narwhal nib unit is totally wrong. I don't know how that idea got into my memory. I pulled the nib unit just now, and *NEITHER* the Asvine nor the Bock 250 nib unit will go into the Narwhal pen. The threads on the Narwhal nib unit are similar, but there are more of them and they start in a different place relative to the end of the collar. 

[Dillo]

I was able to examine both, and the pen bodies themselves are completely identical. I changed from the Asvine nib and feed to a Bock 250 nib unit in mine but I'm now using a Flexible Nibs Factory ebonite housing and feed in mine. Take the O-ring off the end of the nib unit and install it on any nib unit you put in there. I also transferred the front O-ring without any issues

[Paganini]

Great! Thank you!