Nikkor-HC 5cm ƒ2.0 Lens Disassembly

[Blind_spark]

I have an early (1950) example of a 5cm ƒ2.0 Nikkor-HC that I am hoping to clean up. I want to clean the aperture blades and maybe, more importantly, clean up some haze. I sort of doubt this last part, but I can hope...anyways.

I can't figure out how to get into the optical module. I can remove the lens from the focusing helical, but I can't see how to remove the rear or front groups. I can see a spanner screw deep inside where the rear element is - I don't have a spanner (nor can I imagine that one could be both thin and strong enough) to reach it. Conversely, I'm not sure how the front would come out - it isn't like a Summicron or the 1.4 Nikkor where the front simply unscrews.

This lens is a bit of a dog - plenty of scratches up front along with the aforementioned haze. I'd just like to free up the sticky aperture and maybe take away the fuzzy wuzzys. It certainly works though, and I do enjoy the images it can make. I'd like to see if I can improve it; I don't have any intention to send it in just now...

If anyone can offer some insight as to how I proceed and any tips/tools, I would appreciate it. 🙄

***I'm not sure how to rotate the pictures...sorry!

 

[Blind_spark]

On a cloudy day with the sun to my back...

On a cloudy day with the sun to my back...

So, it's not all bad - 😀

But on a sunny day...it flares like mad no matter where the sun is. Any highlight takes on a surreal glow. Which would be nice if I just wanted this as an effect lens. Alas, it's my only lens 😛.

 

[Blind_spark]

Perhaps it is so well machined that I can't see it, but there does not seem to be a seam at which the front would separate. I have removed both the aperture setting ring as well as the scale - it seams to be one solid bit of chromed brass. Is it the inner knurled ring inside the filter ring that needs to be removed? I'll try to document this more clearly when I get home...

 

[Blind_spark]

Thank you for the pictures - however, this does not seem to be the case with the Nikkor. Here is a further image of disassembly. From the bottom - there is the forward most ring (into which the filter screws), followed by the ring on which the aperture scale sits (it has been removed, you can see where one of the set screws goes to hold said scale in place), and finally the ring on which the aperture adjustment ring goes (also removed). From top to bottom, this is one solidly machined piece of chromed brass, despite the appearance of separate components...I am entirely perplexed.

Perhaps this is different than later examples, this being of the first year of non-collapsible construction. I must need a special tool. :bang: Perhaps this is a nut that is nigh-uncrackable 😕.

 

[Jamie Pillers]

Have you tried unscrewing the 'glamour ring'... the decorative ring around the front element with all the Nikon text printed on it? Sometimes those rings unscrew, revealing the next step. I've unscrewed them by using one of those big pint erasers kids use in school. I cut the eraser so that its the same length as the diameter of the filter thread. Then I press the eraser against the glamour ring and turn it. Maybe?

 

[Blind_spark]

Have you tried unscrewing the 'glamour ring'...

I have not - while the front element is anything but free of scratches, I don't want to add more. Also, there seems to be an interruption between said glamour ring and the threads. It must come out though...by an eraser, you say? Could you illustrate?

...My instinct is if you are having trouble understanding this lens, it may be better not to take it apart, since there is likely to be no improvement and you may create a paperweight...

I'm thinking more and more that you may be right in this. I certainly cannot see a way forward (though I can imagine it being right under my nose, so I will keep looking 😀). But, like you said, I may create a paper-weight if I push something I ought not to and I would prefer a less-than-perfect lens I can use than nothing at all. If anyone knows and can show me, I would love to know; if it turns out to be above my skill level I would happily quit while I'm ahead...

But darn it all if I won't at the very least figure it out! 😉 I'm already feeling quite competent taking it apart and fitting it back together; it still makes images!

 

[xayraa33]

I have an early (1950) example of a 5cm ƒ2.0 Nikkor-HC that I am hoping to clean up. I want to clean the aperture blades and maybe, more importantly, clean up some haze. I sort of doubt this last part, but I can hope...anyways.

I can't figure out how to get into the optical module. I can remove the lens from the focusing helical, but I can't see how to remove the rear or front groups. I can see a spanner screw deep inside where the rear element is - I don't have a spanner (nor can I imagine that one could be both thin and strong enough) to reach it. Conversely, I'm not sure how the front would come out - it isn't like a Summicron or the 1.4 Nikkor where the front simply unscrews.

This lens is a bit of a dog - plenty of scratches up front along with the aforementioned haze. I'd just like to free up the sticky aperture and maybe take away the fuzzy wuzzys. It certainly works though, and I do enjoy the images it can make. I'd like to see if I can improve it; I don't have any intention to send it in just now...

If anyone can offer some insight as to how I proceed and any tips/tools, I would appreciate it. 🙄

***I'm not sure how to rotate the pictures...sorry!

Try turning that inside serrated ring with a large piece of stiff rubber to get the front lens assembly out.

This serrated ring is visible in your last 3rd picture that you are showing in your first post.

I had a Tokyo 5cm F2 Nikkor lens in LTM that needed a bit of cleaning and that is how I got at the end element from the front lens assembly for cleaning.

 

[Blind_spark]

Try turning that inside serrated ring with a large piece of stiff rubber to get the front lens assembly out.

This serrated ring is visible in your last 3rd picture that you are showing in your first post.

I had a Tokyo 5cm F2 Nikkor lens in LTM that needed a bit of cleaning and that is how I got at the end element from the front lens assembly for cleaning.

Sweet tap-dancing Christ, that was it! How the rear group comes out, I don't know - but at least that gave me access to the fog, which has mostly come off. So, good news on that front. I used a slightly-too-small Schneider EL-Lens cap as the the friction bit, FWIW.

I may never say it enough, but thanks to all for their tips and pointers. I may borrow my roommate's 5D to make some more detailed photos tomorrow, perhaps a step-by-step. Hopefully this will serve as illustration for those wishing to know, though it goes without saying though - at one's own risk 😎.

 

[xayraa33]

xayraa33 wins the prize.

Funny -- now I can picture removing those elements with my two thumbs on the serration. 20 years since I took one of these apart.

A piece of bicycle tire inner tube placed across that serrated ring and held down by your thumb and index while you revolve that same hand will do the trick if the lens assembly is not screwed in super tight.

It saves the skin on your digits at least 🙂

 

[Blind_spark]

xayraa33 wins the prize.

Funny -- now I can picture removing those elements with my two thumbs on the serration. 20 years since I took one of these apart.

Ouch! Mine was super tight - probably hadn't been moved since 1950. So the hard rubber trick works a treat.

Fred, a piece of bicycle tire inner tube placed across that serrated ring and held down by your thumb and index while you revolve that same hand will do the trick if the lens assembly is not screwed in super tight.

It saves the skin on your digits at least 🙂

The lens cap worked especially well - it was small enough to sit inside the main filter ring, convex so as not to mar the front element, and hard enough so not to shred against the serrated ring.

Needless to say, tomorrow will be real test. 😎 (Once again, this lens has kept me up past my bed-time...)