Quote Originally Posted by q_x View Post

As for frankensteining some lenses, either it's an exercise in machining your own gear, or just being wasteful in terms of both time and gear, but it sounds like you know what you're doing. Having a lens, I'd rather use it as it is. But if you're skilled and you have a lathe, I guess there's nothing stopping you really. Collapsible Industar barrel is something like 19mm wide, there's no space for anything close to f/2 or even f/2.8 diameter, it''l be interesting to watch how you overcome that issue.

I have access to a toolroom, with a Hardinge lathe and a Moore jigborer, so I can machine whatever I need, to whatever tolerance is appropriate, with the exception (for now) of metric threads - there are some ways around that, though. It looks like the focussing mount (inner helicoid) from a late J-8 can be bored out to accept the optical cell of a H-103. I like the Helios because it's a typical clinical-looking double Gauss, just like my 50/2 Nikkor H's.
As for the collapsibel I-61, it may be possible to remachine the I-10/22/50 focussing mount and fabricate a new barrel to accept a (possibly remachined) optics cell from the I-61. I'll most likely end up with examples of these lenses anyway as users, once I do five minutes with a dial caliper will tell me what's possible... maybe a collapsible H-103!

The there are all those M42 Soviet lenses...

For what it's worth - http://forum.mflenses.com/helios-103...on-t53684.html