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Nikkor-P 180/2.8 focus stuck
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PostPosted: Wed Jun 12, 2019 1:59 pm    Post subject: Nikkor-P 180/2.8 focus stuck Reply with quote

Friend of mine gave me her late fathers lens to check and maybe sell. Looks like it was discarded a long time ago because the focusing was totally stuck.

Any idea what to do, just use force (Luke) or try disassembly?


PostPosted: Wed Jun 12, 2019 2:28 pm    Post subject: Reply with quote

try disassembly may be best use of the force


PostPosted: Wed Jun 12, 2019 2:30 pm    Post subject: Reply with quote

I don't know what works best for you, either selling as is or repairing.
But I would advise against using force.

Otherwise you might break lens transaxle https://vimeo.com/77534838 Smile


PostPosted: Wed Jun 12, 2019 4:19 pm    Post subject: Reply with quote

I'm not sure how the focusing collar on that lens attaches, but it bears taking a look at it. It might be something relatively simple, like a screw having come loose, dropping down and binding the mechanism. Anyway, that's where I'd start taking it apart.


PostPosted: Wed Jun 12, 2019 4:31 pm    Post subject: Reply with quote

It's a common ailment of these lenses. It will have to be stripped down, cleaned and relubed. It's not terribly difficult but takes a bit of time. Do not force it, you'll end up shearing the focus guide, and then good luck finding a replacement.


PostPosted: Sun Jun 16, 2019 12:23 am    Post subject: Reply with quote

I've fixed one of these up for a Florida Today photographer. I don't recall what I did exactly for the focus mechanism, only that the lens was one of the easier ones I've worked on.

Follow best practice (JIS screwdrivers, naptha on stuck/adhered threads, stop and assess if something doesn't want to move) and there shouldn't be any issues.


PostPosted: Sun Jun 16, 2019 7:40 am    Post subject: Reply with quote

Mike Deep wrote:
I've fixed one of these up for a Florida Today photographer. I don't recall what I did exactly for the focus mechanism, only that the lens was one of the easier ones I've worked on.

Follow best practice (JIS screwdrivers, naptha on stuck/adhered threads, stop and assess if something doesn't want to move) and there shouldn't be any issues.


thanks!

I been thinking that you could drip some solvent to the helicoid parts not even opening it fully, because putting it back could be a difficult operation.

Any ideas what could be the safest option when I don't want to oil the whole lens.


PostPosted: Sun Jun 16, 2019 8:48 am    Post subject: Reply with quote

kansalliskala wrote:
I been thinking that you could drip some solvent to the helicoid parts not even opening it fully, because putting it back could be a difficult operation.

Any ideas what could be the safest option when I don't want to oil the whole lens.

The safest option is to do no such thing.
You will just make it that much harder for a next guy to properly service it.

Either go inside or sell as is.


PostPosted: Sun Jun 16, 2019 11:30 am    Post subject: Reply with quote

aidaho wrote:
kansalliskala wrote:
I been thinking that you could drip some solvent to the helicoid parts not even opening it fully, because putting it back could be a difficult operation.

Any ideas what could be the safest option when I don't want to oil the whole lens.

The safest option is to do no such thing.
You will just make it that much harder for a next guy to properly service it.

Either go inside or sell as is.


I was thinking lubricating the helicoid guide or rail parts, don't know exactly what they are called, if you open them and unscrew the helicoid, then it gets difficult. Usually you see them when you open the back of the lens. Like these of Helios.



PostPosted: Sun Jun 16, 2019 2:28 pm    Post subject: Reply with quote

I have saved 3 stuck lenses this way. Not sure if it was an issue with the fine thread guide or the actual helical thread.

The only reason I tried this was because I could clearly see the helical/threads from the top and bottom and had a direct path to use only one tiny small drop.

The product was the original formula of Pedro's ICE Wax PTFE lube and it runs like water.

After quickly rotating the lens to walk that single bead of liquid around let gravity do its work. Finished with a heat gun set to a low temp around 100 degrees or until the casing was warm to the touch.

Unlocked a Komura m39 105/3.5, Kilfitt 150/3.5 and unlodged a piece of sand from a Takumar 35/2.3

Also used it on any metal to metal surface like the fine thread guide. If you clean that part it usually works smoother with a lighter lubricant than what is typically used on the helical.


PostPosted: Mon Jun 17, 2019 2:24 am    Post subject: Reply with quote

kansalliskala wrote:
I been thinking that you could drip some solvent to the helicoid parts not even opening it fully, because putting it back could be a difficult operation.


Actually, putting it back is easier than cleaning after someone who tried to fix it with solvent, or, as was the case with a 50 that ended up on my worktable this week, superglue.


PostPosted: Mon Jun 17, 2019 7:39 am    Post subject: Reply with quote

Gardener wrote:
kansalliskala wrote:
I been thinking that you could drip some solvent to the helicoid parts not even opening it fully, because putting it back could be a difficult operation.


Actually, putting it back is easier than cleaning after someone who tried to fix it with solvent, or, as was the case with a 50 that ended up on my worktable this week, superglue.


could be, must just mark the correct threads somehow

with my Helios it was actually the focusing ring thread itself that was stiff, not the helicoid