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Micro nikkor 55mm f/2.8 mystery spring

JRoosa

Member
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Jul 31, 2014
Messages
112
Location
Colorado, US
Format
35mm
My lens started making a "crunch" noise at full extension, and I have been having some trouble with what feels like a small piece of sand in one of the half dozen helicoids in it. I took apart try to clean out what I thought would be a few grains of sand, found a few pieces of grit and removed them from the helicoid grease with a Q-tip, and then found this small spring sitting on the table.

It's not the return spring on the front aspect of the aperture assembly...that's there.

The long lever that holds open the aperture is still sprung.

Both the FA and FM that I have recently used it with are working correctly as far as I can tell. No no springy bits are failing to spring back.

Any thoughts?

J.
 

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The crunching that developed today felt very different than the sand. The sand grains almost lock up the focus, but the crunch felt more like a little spring getting smooshed now that I think about it.

Focus is smooth as can be now.

J.
 
Just curious.

What does the f stop ring feel like when you turn it? Do you feel the indents?
 
You may have seen this, but you may want to check out this: http://akikorhonen.org/projects/cleaning-of-a-micro-nikkor-55mm28-ais

But, if the aperture blades are snapping back open, and everything appears to be functioning properly, personally, I would put the spring somewhere safe, and use the lens. If something isn't working right, then you need to replace that spring (the one you have looks pretty done). Other than that, no clue...
 
I think it must be 2 springs inside the lens, one in the aperture mechanism itself to keep blades close and one spring in the rear flange assembly to help the aperture spring. Without last spring the aperture one spring can do the job but with difficulties.
Check flange assembly for mounting points, hooks on the lever metal piece ......
Put here more detailed pictures. Find service manual to see if is one or two springs inside your lens.
i will try to find one for you.
 
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Thanks. I've seen various pages about this, but this is the first one I've seen makes me think I can actually clean the aperture blades on mine. They are sluggish and I can't use my lens, and I like it.
 
One thing not mentioned on those cleaning sites is that there is an eccentric screw that allows fine rotational adjustment of the guts when you put everything back together. If it is misaligned, then the aperture doesn't quite work like it should. Mine wouldn't quite open all the way until I figured it out.

It's a flat head straight slot screw. You'll know it when you see it.

I looked everywhere and couldn't find a place for it. I also looked through those websites looking for a similar spring. It looks just like the one that works the aperture assembly, but that one is in place, except it's brass colored instead of the black in the pictures.

I have a theory. When I bought the lens, it was filthy inside. The guy at the shop took it in the back room and messed with it for a while. When he came back, the glass was clean, but he had to try a couple times to get it back together because the focus would lock up. He was really frustrated with the whole thing.

I wonder if in the process of cleaning the glass, the aperture spring went "sproing!" and disappeared. Maybe he found another spring, put that one in, and assumed the other one was forever lost in his shop. Instead it was stuck somewhere inside the lens causing the focus to intermittently lock up.

I'll hang on to it in my big box of treasures, but everything seems to work OK, and I can't see anywhere that it would hook into.

Nikon wants $199 to do a full CLA on it, by the way. If I could sell it for $150, kick in the $199 CLA cost, and scrounge another $60, I could get a brand new one.

Thanks, Nikon, but no thanks.

-J.
 
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Oh, the rear flange has a spring deep inside somewhere. It is in there and working to keep the long armature that engages the aperture mechanism pushed against the lever inside. So that's not it.

In this photo, the ring with the camming surface that opens and closes the aperture looks like it should be sprung, but in none of the other pictures I see is there a spring to be found attached to it. It gets rotated by the armature coming from the aperture adjustment ring, and that armature has a slot in it so that it pushes this ring in both directions. It doesn't seem that spring tension would be helpful here.



Also, at 11:00 you will find the eccentric screw I was talking about. Once everything is apart, the screw drifts from its set point.

-J.
 
I went with my theory. The found spring is much lighter than the silver one in the lens. Looking at the photos, the found one looks more like the one that is supposed to be there. The wire is thinner and it's the right color. I swapped the two springs (the smooshed one isn't quite as bad as it looks) and everything works fine.

I'll keep the other one, but I think that it was a makeshift replacement.

Now I wonder where it was hiding in there for months.

Also, I'm getting really good at taking this lens apart and getting it back together again. If I could find the right grease for it, I could completely overhaul the thing. That would take care of the bits of sand that might be hiding in the helicoids. Maybe that was the loose spring after all.

Focus is butter smooth now.

-J.
 
That's where I put it. The spring in the flange is buried and can't really fall out.

I will look into the tri flow. I'm sure my local hardware store has some.

J.
 
See post #9 for a picture of that screw.

I havent had the helicoids apart in mine. Apparently you need to mark things to get them back together right. You don't need to take them apart to clean the blades though.

You also need to note the orientation of the aperture assembly when you take it off. There are three ways to put it back on and only one is right.

Good luck.

J.
 
Got it! I looked at the photo and decided there was only one that looked like what you were talking about, then saw the 11 o'clock comment, and yep that's the one. Great, now there are photos to follow all the way. Thank you very much. I won't do it until I've got a few quiet uninterrupted hours available, but I will give it a try. And I'll pay attention to the aperture assembly.
 
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