Elmar 5cm 3.5 DIY CLA worth proceding?

[Fernando Mattos]

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Hi! Just bought my first Leica, a IIIa from 1937 with Elmar 5cm 3.5 (don't know the year, can it have come with the camera?). The camera and lens are not in good shape, and both needs a CLA.

I live in a small town in Brazil, and the only repair shops are distant and busy. Adding to that, I intend to keep and use the camera for the rest of my life, so I thought it would be more pratical to learn mainteinance of it myself. I've already cleaned and opened other lens and cameras before, although not all of them returned to operating condition after that.

So, I'm opening this topic to document the process, and perhaps help others. Also, I'll need a help myself with some steps, and hope some of you can help me.
First I decided to service the lens. For the IIIa, I'll open another topic when I start.

 

After waching these videos (video 1 video 2, video 3) and reading some forum topics, I've, so far:

- Cleaned and grease the focus helicoid as it was a bit stiff in the limits. Disassembly was easy, but reassembly was not. It's dificult to know when the threads fit, and the first turn of reassembly was a bit stiff. But in the end, not without some emotion, I've could fit both parts again, in the right place, and without ruining the threads. If I'd do it againg, I would try to clean it without separating the parts of the helicoid. Also, seems important not to remove the main outer cilinder from the base plate, since it can be hard to put it back.

- The pin tab that locks the lens in infinity was a little bent. Just unbent it carefuly with pliers (yet, left some marks...).

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- Removed the back light trap ring and released the lens barrel. The back ring that holds the lens barrel was really stifff, and I could only release it after adding some WD40 (I know, I know...) carefully with a pin in the theads and waiting some hours. And it is worth mentioning that the commom lens spanners don't fit there, I had to reshape mine with a file.

- Finaly, with the optical barrel free from the lens body, I've cleaned the old grease from the apperture ring (it was stiff) and lightly regreased it.

Up to this point, I have not touched the lenses, but only light cleaned the external glass surfaces. But the interior of the glasses and internal elements seems to need some cleaning, and there are some black flakes (not loose) inside in more than one place. Does anybody know what can it be?

 more images attached bellow.

 

At this point I'm deciding if I'll open the lenses barrel. If I do, what do you recomend? Front first? If front, how do I detach the front elements? I see a inner notched ring in front, but it seems to hold only the frontmost glass, not the front set of lenses. I tried to release the set, similar to unscrewing a filter, but it is stuck. I've read people using nail polish removal (acetone), but don't know where to apply. It seems to me that should be on the line in the picture bellow (barrel without aperture ring), can someone confirm, please?

 

 

 

Edited September 22, 2024 by Fernando Mattos
Did not append pictures before

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[Fernando Mattos]

Well, continuing the adventure! Perhaps I should have name the topic "Learn from my mistakes", because I've just made the first one!

 

It hapens that trying to remove the front set (the one above the yellow line in the previous post), I ended loosening the inner noched ring tha holds the first glass. Looking into the lens diagram (found here), the outer lens set have only one glass, so I gave up removing all the front set and removed only the front glass.

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The mistake I made was to manipulate the lens and the apperture leaves without the aperture ring attached. It happens that the screws that hold the aperture ring, holds it to the ring plate that holds the aperture leaves in place, and manipulating it without the aperture ring made it to move back and the leaves came out of position. What a nightmare! After a brief heart attack, I just put the lens barrel front side down, and with some gentle taps and patience, made all the leaves pins into place again. When all the pins was back to place, the inner ring plate that holds and actuate the leaves came back to a front position, and the screw holes was again visible and in position for screwing back the apperture ring.

The leaves back in place:

After that, I finaly evaluated the situation of the black flakes. It seems to be some black coating of the border of a glass from the back elemments that flaked off. Buffed most of loose material with a rocket blower and a soft brush. 

 

 

 

Now I need to remove the back elements, since there are black flakes between them also, and some fogging. I've applied acetone to the orange line in the picture bellow, in order to remove the part marked with {, but no sucess to far.

 

I don't have that rubber rings for lens, and the rubbers I tried at home are not so grippy. I've seen someone  drill small holes to the ring, so that a pointy lens spanner could fit. I don't have a drill press, but I thought to cut two notches to fit the flat point spanner. Any other idea?

 

Just thought that I also may just remove the back most glass, and this will give acess to the space between the glasses...

 

Edited September 23, 2024 by Fernando Mattos

[jerzy]

vor 20 Minuten schrieb Fernando Mattos:

and this will give acess to the space between the glasses.

you might need good clamp tool (2 dimensions) to unscrew the rear part. It has all 3 lenses together and very rarely you need to open the rear group, it is hermetically closed. Fog deposits on surfaces adjacent to aperture and if you have the firt lens out then you may clean the other surface through the open aperure. of course, it is better to unsrew the rear group, but if you do not have appropriate tools... do not drill or cut anything there, the last two lenses are cemented and you may happen that you will end up with separation. It is better to clean it through the aperture. Congrats for arranging blades, I have a simplke tool for this

[jerzy]

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[jerzy]

P.S. in German part, Leica Historica, there is a thread "Do it yourself..." worth looking into, is however in German

[jerzy]

FYI - this is rear group unscrewed, you may unscrew as well one element (2nd lens counting from front) but you may reach uit as well through aperture

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[Fernando Mattos]

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19 hours ago, jerzy said:

P.S. in German part, Leica Historica, there is a thread "Do it yourself..." worth looking into, is however in German

Thank you for all your comments, @jerzy! I would not get to the german topic alone. Ich spreche kein Deutsch, but the browser translator made it possible to understand. Still in the first pages, though.

Regarding this lens, after your comments, I've decided to just clean the inner back lens through the apperture, as you sugested. It still have black flakes between the glass 2 and 3a in the image bellow, but not so much. I also see, when strong light hits at certain angle, someting inside the back group that ressambles fungus. Not sure in which surface it is, I'm hoping not to be in the cemented suface (3a/3b).

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Anyway, cleaning the front glass revealed that it is somewhat unpolished in the front surface, possibly from carring the camera around without any cap. Is it fixable? Repolishing a glass element is something doable at home?

This unpolished surface is worse than the fungus in the back element mentioned above. Adding to that, I don't have the spanner wrench or other tools to safely release the back group, so I'll leave the back element alone, and close the case (an the lens) for now. I'll shoot some rolls of film through it and see in the future if is it necessary to invest more in this.

Thank you for your help. I'll open a new topic when I start the IIIa body.

[jerzy]

vor 2 Stunden schrieb Fernando Mattos:

Repolishing a glass element is something doable at home?

to some degree yes, only very fine scratches, respectivelly if glass is dull (but no fungus). Be aware that when polishing you remove very thin layer of glass thus it may impact optical characteristic. I use cerium oxide and soft tissues to polish and do it carefully

[jerzy]

vor 2 Stunden schrieb Fernando Mattos:

It still have black flakes

forgot about this earlier.... it is common that old lenses might have black dots and this is not dust or dirt. Very often these are air bubbles that came there in the process of melting glass, so long before lenses were cut and polished. Some are smaller, and these you see as black dots, some are bigger and you may see that there is a black circle, transparent in the middle. Check them with magnifying glass. Air bubbles (inclusions) are not impacting performance of the lens