NIKON PlanApo 100X/140 oil that is a PlanApo 60X/140 oil

[apochronaut]

1.482 ! Maybe it's Ukrainian sunflower oil. They got a deal. You might as well use Glycerin. II's a lot cheaper, you can buy it at the pharmacy and it cleans up with water.

No, in order to achieve 1.4 N.A. and anything resembling resolution that would justify that N.A., you need 1.51-1.52. and both the condenser and the objective need to be oiled. If your condenser isn't oiled the objective N.A.becomes about 1.2, when it is oiled. An objective is a type of light pipe and it can only pass what it is provided with.
The objective is expecting N.A. 1.4 light and that can only be achieved with as homogeneous a condition as possible, so from the top condenser lens right through the front lens element of the objective, the n is best kept consistent. The objective is engineered to correct for a predictable amount of spherical aberration once the light passes through the first lens. If there is more, then you lose contrast and resolution and the higher the N.A. is over .80, the worse the problem becomes.

So you have a plano front surface and a plano back surface and 1.4 N.A. Normally lenses in an objective are arranged in ascendng diameter in order to achieve the f.o.v. the barrel is capable of while attaining the desired planar and aberration corrections, which can be done more easily with larger diameter lenses. That's the reason for a fatter barrel and the front lens cell architecture is abruptly tapered so as to allow the expanding ray bundle to broaden out into the ever larger lens diameters.Once the desired corrections are achieved in the middle lens groups, the bundle is compressed through a rear lens group that does some final aberration fine tuning.

I suspect you are missing a front bonded/embedded lens element in your diagram and that causes the front lens element to be larger than normal and of it's sort of glass column shape with straight sides. Normally a 1.4 objective would have a plano/convex front element with a deep rear curvature. The embedded lens allows the meniscus lens to be relatively smaller . I was concerned that the embedded element might be loose, thus the questioning around that. That , if so would be a game changer. Is that still up in the air, or is it the entire front lens element loose?

If it is just the main front element , and the oil was just trapped between the front embedded doublet and either the meniscus element or the next element , then it looks like the mount of the entire front element has failed, so cementing it as forward in the front cell as is possible is required. There is no way of removing that rear plano surface so you can get at it?

[stjepo]

"1.482 ! Maybe it's Ukrainian sunflower oil. They got a deal. You might as well use Glycerin. II's a lot cheaper, you can buy it at the pharmacy and it cleans up with water." I was using it. This is the one sold here, there are others but they don't even give the index n.


"Is that still up in the air, or is it the entire front lens element loose?" I wouldn't know what to answer you, I only see the front lens that moves, it even allows me to insert a small paper that goes under the metal in its entire circumference, I have taken advantage of this to clean it since a lumpy yellow substance comes out.


"I suspect you are missing a front bonded/embedded lens element in your diagram and that causes the front lens element to be larger than normal and of it's sort of glass column shape with straight sides." As always, I am surprised by your knowledge. I started looking for what you were saying and a small glow on the side of the "cylinder" surprised me. I managed to make several images of which I am sending you the best ones.

alien02.jpg (52.52 KiB) Viewed 1988 times

alien03.jpg (57.37 KiB) Viewed 1988 times

"There is no way of removing that rear plano surface so you can get at it?" I guess it's through those white silicone dots, I don't have much of an idea. If I access it, I won't know how to mount it properly or what to glue it with, but there seems to be no other way because this lens is "decessit." You'll tell me what I should do.

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[apochronaut]

I had assumed that you had completely removed all of the lens cells from the barrel and were viewing the back of the front lens cell. No wonder I was confused about why you would be seeing a plano surface at the back of the first cell and mentioned that it would have been a lot easier if the oil would have been between cells instead of in one.
The 4 plugs are for centering the second cell.They are not tight and usually you can push the two lens cells out the back and put them back in with little disturbance to them.
You have to try that if you want to tighten up that front lens.

You will then have to make sure the white seal around the front bezel doesn't leak.when reassembling.

[stjepo]

What type of glue should I use to fix the front lens? I will need your help to figure out the order of the lenses and of that meniscus that is out of place.

The four white dots that center the lens are made off some type of plaster paste. What should I use to reseal it?

[stjepo]

Could I use Cyanoacrylate glue for the front lens and high quality silicone for the four white dots?

Thank you

[apochronaut]

Don't worry about the plugs. Just push the front cell through and mark both cells, so they go back the same way. You probably need to refer to earlier posts.
I have usually used epoxy, obviously on surfaces that are not optical. Let it cure for a week or two before reassembly. Don't use acetone around it ever but it is stable with commonly used degreasers used on a microscope objective, notably xylene ,n-heptane, ipa etc.
First look and see if there is any way of restoring or partially restoring the mechanical structure that originally held the lens in place. It needs to be in exactly the same place it was originally. On one objective I restored the broken furl to as much of it's original integrity as was possible and strengthened it with silver solder. That worked well enough but I still used epoxy to seal off the lens.
I don't know if epoxy is vulnerable to sunflower oil, though. It's not in the charts.

[stjepo]

Done!!!

The Nose

IMG_0604.JPG (36.42 KiB) Viewed 1889 times

Another

IMG_0605.JPG (40.17 KiB) Viewed 1889 times

The dead body

IMG_0606.JPG (31.17 KiB) Viewed 1889 times

Which glue to be used in the metal bezel?

[stjepo]

Lens

LENTES.jpg (29.26 KiB) Viewed 1872 times

[Scarodactyl]

Could I use Cyanoacrylate

No cyanacrylate near lenses, the vapors can fog them.

[apochronaut]

Could I use Cyanoacrylate

No cyanacrylate near lenses, the vapors can fog them.

Yes. renamed cryanoacrylate for optics.

[apochronaut]

Done!!!

The NoseIMG_0604.JPG

AnotherIMG_0605.JPG

The dead bodyIMG_0606.JPG

Which glue to be used in the metal bezel?

Can you photo the inside of the front bezel and your tears.

[stjepo]

Yes. renamed cryanoacrylate for optics ¿?

Which glue should I use? I have no clue. Brand? Composition?

The Bezel best pictures:

[stjepo]

Front of frontal lens: In the first in the bottom glass of my Binocular microscope.

[stjepo]

Internal side of the frontal Lens:

[apochronaut]

Yes. renamed cryanoacrylate for optics ¿?

Which glue should I use? I have no clue. Brand? Composition?

The Bezel best pictures:

Is that inner ring in the first pictures, the diameter of the front lens?

[stjepo]

Which type of glue I should use for the bezel?

1

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2

2.jpg (55.23 KiB) Viewed 1728 times

3

3.jpg (63.02 KiB) Viewed 1728 times

[stjepo]

Parts

[apochronaut]

So, that smaller relief presumably has a raised lip that was at one time a tight furl around the front lens. Centering is important. Does the front lens fit exactly in that relief, so that it is quite automatically centered?

[stjepo]

The lens is centered thanks to a small bevel on its flat side. Still I have no idea which is the right glue to fix It back to the bezel.


Maybe I may be asking too much.

[apochronaut]

I use epoxy. You're not there yet. The area around the lens window looks beat up a bit. That could be just the photo. Is it completely flush and flat?

[stjepo]

Yes, there are small dents. I cleaned the area and then with the head of a flat screw and with great care I left the surface flat again.

[apochronaut]

That surface needs to be exactly as it was when the objective left the factory because it establishes a spatial relationship to the next mounted lens.

Once I am sure the area around the front window is good, here is what I do.
Make a tiny piece of cork with a slightly concave surface, from a wine cork. A piece of citrus peel will do, if you don't have cork. Once you are sure that the front surface is exsct and centering is assured you can put a very tiny bead of epoxy just back from the perimeter of that window. Just enough that it doesn't squish into the orifice once the lens is centered and pushed flat to the bezel. Make sure it is centered and press the lens tight. Put the tiny piece of cork on it and a small weight. Let the epoxy set for a day.

Once set, you can see if the factory metal bead or furl can be at least partially restored. Reinforce it with an epoxy bead around the side of the lens but be careful. It is N.A. 1.4, so a considerable portion of that rear hemisphere sees the front plano window. Let the epoxy cure for at least a week.

Hopefully, the positioning is all marked and the components can be reassembled and it works. If it turns out to be off center, that is a whole other issue.

[stjepo]

Thanks to the help of Apochronaut , for which I am very grateful, I have been able to reach to this point, now it is time to work and wait patiently for the drying and assembly periods, so this thread is pending the results of my "botching" ( I'm kidding)

Will we recover this objective or not?

It will rain tomorrow?

Has the bull died? (For PeteM)


"Does she...or doesn't she? Only her hairdresser knows for sure". (Clairol, 1957)

[apochronaut]

A little bit a graphic reminding me of The Time Tunnel, which could have featured Clairol ads, althogh those of a little bit in the future.

[stjepo]

In the recovery room

[apochronaut]

patients is a virtue.

[PeteM]

In the recovery room

Now, that's funny. My only concern, Stjepo, is that with such an attentive and attractive nurse, Mr. Apo is likely to linger in intensive care.

[stjepo]

PeteM, sorry for the joke, I did it to relax the tension I had reassembling the Nikon objective.

Just trying to put the little 'tear' in the front made me suffer a lot. To apply the epoxy and place the small front lens, I practiced for several days. I was able to do it without staining lens with epoxy and I think I fitted it properly in the center of the objective front (time will tell). Also placing the golden washers inside was a pain in the ass (the Japanese put them inside to punish all those who dare to open these lenses).

After the recovery period I prepared this 'little welcome party' whose images I now show (I have no other way of knowing if the results are bad, mediocre or good so I have compared it with other 100X objectives, with and without 'corn' oil)

Apochronaut you are an excellent remote 'surgeon', I hope the results are up to par with your lessons.

PeteM thanks for pushing me to try to open it, anyway "In for a penny in for a pound".

[PeteM]

Sjtepo, it looks like the surgery was a success, bringing back Mr. Apo from the dead.

[apochronaut]

Big round of applause, Steve. Well done. Now, if that nasty oil will just stay put. Keep acetone away from it. Epoxy loses it's will to live around acetone but happily your objective hasn't and pulled through.
be even better with 1.52 oil.