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Disassembling M39 Komura 135mm f/3.5
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Posted: Sat Mar 22, 2025 3:51 am
Post subject: Disassembling M39 Komura 135mm f/3.5
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Posted: Sat Mar 22, 2025 3:51 am
Post subject: Disassembling M39 Komura 135mm f/3.5
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Hi all,

Any Komura experts that can help with this one? Lens helicoid is very stiff, want to disassemble, clean, and relube. Can't figure out how to get this lens apart though. When I remove the screws near the mount, the mount doesn't come off, it just allows the silver sleeve to slide up, but not enough to reveal the helicoid keys. I tried removing the three screws on the aperture ring, thinking the aperture ring might unscrew, but it doesn't budge. Looking into the rear of the lens, it doesn't seem like there is a ring or sleeve to unscrew to separate the lens as some other early Komuras have. Also tried unscrewing the collar that has the distance marks, but doesn't seem like it's supposed to come apart.

Any thoughts on how to get into this one? Thanks!

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Posted: Sat Mar 22, 2025 4:46 am
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Posted: Sat Mar 22, 2025 4:46 am
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Unscrew the name ring? Just guessing.


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Posted: Sat Mar 22, 2025 5:58 pm
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Posted: Sat Mar 22, 2025 5:58 pm
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visualopsins wrote:
Unscrew the name ring? Just guessing.


Forgot to mention, tried that too and removed the front element, nothing else can be removed from the front.


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Posted: Sat Mar 22, 2025 11:20 pm
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Posted: Sat Mar 22, 2025 11:20 pm
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Sometimes lens barrel separates, unscrews, about the aperture. Grasp barrel by mount and by front, unscrew.


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Posted: Sun Mar 23, 2025 1:24 am
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Posted: Sun Mar 23, 2025 1:24 am
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visualopsins wrote:
Sometimes lens barrel separates, unscrews, about the aperture. Grasp barrel by mount and by front, unscrew.


Thanks for the suggestions, I'm trying all of them again. I'm not able to unscrew by hand, feel like I might break something if I tried more force. This one really has me stumped, keep the suggestions coming! Smile

When I remove the 3 screws from the aperture ring, the aperture ring doesn't budge from its normal travel. Thinking it must unscrew as it doesn't just slide off, but don't want to force it too hard.


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Posted: Tue Mar 25, 2025 12:36 am
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Posted: Tue Mar 25, 2025 12:36 am
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visualopsins wrote:
Sometimes lens barrel separates, unscrews, about the aperture. Grasp barrel by mount and by front, unscrew.


Took all my strength to finally get it to unscrew, don't think it's ever been apart before. I've CLA'd hundreds of lenses, this one has unique construction. The helicoid key sleeve just slides on and then the whole thing is screwed into the mount. Time to clean and relube, thanks for the suggestions.


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