Replacing lens elements in Kiev mount J-9

[Hamster]

Recently, I have come across a 60s vintage Kiev Mount Jupiter-9 in my neighbourhood camera store. Unfortunately, the front element of this lens is badly scratched and the internal elements show signs of having been etched by fungus. Now it is very troublesome for myself to mail order a lens from aboard as there will be a world of paperwork and burocracy to wade through. So I come upon the idea of repacing the elements of the Kiev mount J-9 with ones from a M42 MC J-9 of Current manufacture, the M42 J-9 is plentyful and easy to find where I live.

My question to you all is, have anyone had the experiance of doing this "transplant"? Persumably the lenses are of the same formulation and therefore the lens element would be of similar dimensions. If this is indeed possible, then it would be wonderful because if my transplant is successful, I can have a Kiev mount lens that have the full benefit of multicoating!

I would be more than happy to post photographs of this operation if it is indeed posible.

May I also ask if anybody here had both Kiev mount J9 and M42 J9 or Kiev J9 of different vintage? If indeed you do, can you possibly do a quick measurement of the diameter of the rear lens element and see if they are indeed the same size? Even if they are not the same size, maybe I can ask a local Eye Glasses shop to have the elements grinded down for me.

[Xmas]

To warrant success you need to be sure the glass is the same type, and form, and even then any shims would need to be custom fitted.

The lowest risk is to pick two lens made in the same year.

The optics in a lens are not like specs their peripherys are coaxial and concentric to very high tolerances.

The pre war Zeiss lenses needed high tolerance mounting. They were statement lenses designed to bury the upstart Leitz

Unless you want a really difficult project I'd suggest finding another lens with perfect optics, and poor mechanical cusmetics, they are not that expensive.

Noel