lukx
Well-known
Hello everyone,
after thinking about it for a long time, I have now purchased a nice pre-war Jena Sonnar, Serial 189xxxx, so made in 1936. It is uncoated as far as I can tell.
There is a slight amount of haze on some elements, as well as a VERY oily aperture. I would like to give it a careful clean.
I have removed the outer barrel, the back triplet with shims, the name ring and front element, and the aperture barrel. What remains is the main barrel with aperture and the first (front) triplet inside. That triplet needs to be removed before I can clean the aperture blades and clean the old grease out.
Looking in from the front, there are two notches for a spanner. I have tried to screw it off with my spanner, but so far I have had no success removing the triplet. The spanner is dangerously close to the frontmost element of the triplet, so I have to be very careful and not use brute force. But I see no other way to get the triplet out.
Later versions seem to have the triplet in a brass housing that can be pushed out, but this does not seem to be the case here.
Am I missing anything? How to remove the front triplet?
In case of success: how do I best clean the old uncoated glass?
Is the glass very soft?
Can I use lighter fluid?
Do I have to be careful not to soften the lens cement?
Thanks in advance, have a great day everyone.
after thinking about it for a long time, I have now purchased a nice pre-war Jena Sonnar, Serial 189xxxx, so made in 1936. It is uncoated as far as I can tell.

There is a slight amount of haze on some elements, as well as a VERY oily aperture. I would like to give it a careful clean.
I have removed the outer barrel, the back triplet with shims, the name ring and front element, and the aperture barrel. What remains is the main barrel with aperture and the first (front) triplet inside. That triplet needs to be removed before I can clean the aperture blades and clean the old grease out.

Looking in from the front, there are two notches for a spanner. I have tried to screw it off with my spanner, but so far I have had no success removing the triplet. The spanner is dangerously close to the frontmost element of the triplet, so I have to be very careful and not use brute force. But I see no other way to get the triplet out.

Later versions seem to have the triplet in a brass housing that can be pushed out, but this does not seem to be the case here.
Am I missing anything? How to remove the front triplet?
In case of success: how do I best clean the old uncoated glass?
Is the glass very soft?
Can I use lighter fluid?
Do I have to be careful not to soften the lens cement?
Thanks in advance, have a great day everyone.
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