Hard focusing 55mm Micro Nikkor Ai solution!

[DrEntropy]

ISTR both Greg and I have this lens with the same problem. Found a very comprehensive video for the fix. On top of that, the guy is fun to watch and listen to as he does the job. Long video because the process is fairly complex. He does a great job of detailing it.

55mm Micro Nikkor repair of stiff focus.

Only things I'd do differently are to scribe the indexing marks on internal parts (not visible when lens is assembled) as the disassembly goes on. Pen marker for external index marking. The other thing is to use cotton cloth (old t-shirt pieces) instead of toilet paper. Less chance of leaving small "lint" fibers inside the lens.

 

[GregW]

If you want to re-start your repair business, I can box mine up to send you. The focus ring is pretty locked at first, but does loosen up with a back and forth motion. Gaining a little more range with each pass.

 

[DrEntropy]

If you want to re-start your repair business, I can box mine up to send you. The focus ring is pretty locked at first, but does loosen up with a back and forth motion. Gaining a little more range with each pass.

Mine loosened up the same. If I decide to try the service on it and have it come out well, we can talk. I've not been into one before, so the first go would be an exercise in what NOT to do, IYSWIM. Right now there are too many things on our plate to commit to it in any event.

 

[DrEntropy]

A clarification and a suggestion:

Just looked at my 55mm, it's an ∱3.5, not the ∱2.8. Forgot, hadn't paid attention 'til now.
If you can get hands on a "jewelers" needle oiling pen you might be able to do a DIY temp "fix."



Small drops of "instrument oil" around both sets of helical gears has loosened this one up to nearly normal. That inner threaded barrel is between the steel metal inner and black sleeve at the red dots. Please excuse the quick-n-dirty photos. Working it thru the range after letting it sit for a few minutes with the oil.

 

[GregW]

I may try a heat gun on it first. I don't have any oiler that small. I think my insulin needles would be too small to pass oil.

 

[DrEntropy]

Likely any oil that would be light enough to pass through a syringe would have a good chance of migrating to the diaphragm in time. The heat gun (moderately applied, I'm sure) will likely work. Maybe set it out in direct sunlight for some time first, as a sorta-kinda trial?

 

[GregW]

I've successfully repaired a glass lamp shade by soldering with a heat gun. I didn't have a propane torch at work so I thought "why not?" Worked pretty well actually.