Possible to lubricate iris-equipped objectives?

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Timor
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Possible to lubricate iris-equipped objectives?

#1 Post by Timor » Sun Mar 10, 2019 3:47 pm

Another maintenance question, don't know if anyone can help with this.
I have a couple of AO iris diaphragm objectives, 50x and 100x (#1016 and 1014). The collars which open and close the iris move smoothly enough, but the 100x in particular needs a fair bit of force. When I tried it on the scope, I found that instead of opening the iris I was unscrewing the objective from the nosepiece.
I wonder if it is possible to put a tiny drop of oil or WD40 at the top and bottom of the collar (shown by arrows in the photo) to loosen it slightly?
I'm guessing the answer is probably no, as I don't suppose the iris can be completely isolated from the optics.
Any ideas would be welcome.
Tim
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75RR
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Re: Possible to lubricate iris-equipped objectives?

#2 Post by 75RR » Sun Mar 10, 2019 4:34 pm

I would suggest that you open and close the iris repeatedly with the objective held in your hand. (without forcing it)

With any luck you should notice that it begins to open more smoothly, if it does, then continue to open and close it until you are happy with the movement.

If that does not work, then heating the objective in a low oven for 15 minutes and then manipulating the iris might do the trick.
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Bryan
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Re: Possible to lubricate iris-equipped objectives?

#3 Post by Bryan » Sun Mar 10, 2019 4:54 pm

I’ve had some luck with this on old camera lenses. What 75RR said about heating it can help but I usually use a hair dryer. That way you avoid over heating it and you can keep adding heat as you work it. If the problem is hardened grease this can help but sometimes the grease will re-harden when it cools causing the problem to persist. Sometimes it works. If the ring has been damaged so that it is no longer round then you probably won’t have any luck. I would avoid using oil because it can easily go places that you don’t want it.

PeteM
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Re: Possible to lubricate iris-equipped objectives?

#4 Post by PeteM » Sun Mar 10, 2019 6:03 pm

Just to add, my experience with WD40 is that it leaves a residue. It's fine as a cutting fluid for aluminum, displacing water, and a sort-of rust protectant and/or solvent. Wouldn't use it as a quality lube for anything.

MicroBob
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Re: Possible to lubricate iris-equipped objectives?

#5 Post by MicroBob » Sun Mar 10, 2019 7:34 pm

Hi Tim,

don't use WD40, Pete is exactly right about the proper uses of it.
With heating a microscope objective I would also be very careful to avoid damaging cemented lens groups. 40°C shouldn't be a problem, so you might carry it in the trouser pocket in an objective container and move it from time to time. If there is no mechanical damage it will be hardened immersion oil or grease and possibly dust. In the long term it will be probably necessary to dismantle it and clean it.

Perhaps Apochronaut has had such an objective apart and can give some hints?

Bob

Timor
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Re: Possible to lubricate iris-equipped objectives?

#6 Post by Timor » Sun Mar 10, 2019 10:11 pm

Thanks everyone for the thoughts and suggestions. It's good to have somewhere like this to get advice.
The consensus seems to be to try gentle heat and avoid the use of oil, particularly WD40, so I'll do that.
75RR, I think my oven may be a bit less clean than yours, it doesn't. look a very objective-friendly environment. I'll find somewhere warm to leave the objective, maybe somewhere over the lamp housing. Since reading your response I've spent some time opening and closing the iris, and already it seems easier to turn. In a day or two I'll put it back on the scope, try to fit it more tightly to the nose piece, and get in the habit of turning the collar a few times each time I use it.
Both objectives, and the scope they were on, looked as though they hadn't been used much recently, and I suppose it's not surprising they stiffen up to some extent.
It would be interesting to know if they could be disassembled, although from what I've read taking objectives apart isn't something to be undertaken lightly.
Thanks again to all.
Tim

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Re: Possible to lubricate iris-equipped objectives?

#7 Post by PeteM » Sun Mar 10, 2019 10:33 pm

Despite small and large shop ovens, multiple heat guns, and micro to macro torches -- this cheap tool is the one I use for things like freeing up frozen optical parts. It will also speed up the drying of touch-up paint and glue -- and do heat shrink tubing -- slowly:

https://www.amazon.com/gp/product/B000X ... UTF8&psc=1

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Re: Possible to lubricate iris-equipped objectives?

#8 Post by apochronaut » Mon Mar 11, 2019 1:04 pm

I wouldn't undertake breaking down a functional iris objective, unless you have already done one beforehand and have an idea of the mechanism. Objectives fit together in many different ways. Fortunately, the one you have is usually easy to repair, without tearing it apart.

Heat is not the best way to solve this problem. Lubricant can lose it's functionality in two ways. One, is that the volatile components evaporate and what was once grease, becomes like wax. The other is a complication of the first, through packing of the lubricant. Intermittent movement grease has the quality of maintaining it's distribution. Usually, such a grease has been used, so heating a grease that is still in distribution, temporarily softens it but once it cools, the hard consistency returns and there is little improvement because the grease has lost it's pliability. Hard grease that has packed here and there, when softened with heat, will redistribute more evenly into thinner films and when rehardened will facilitate a smoother , easier motion for a while, until it repacks. In both situations the best method of repair is to remove the old grease and replace it but in some instances, grease that is only partially hardened can be softened with a very small amount of thin oil.

I have used WD 40 for very stubborn, seized rings and collars with success occasionally but the objective from that point on and for some time, is never to be in a cannister until you can not smell WD 40 anymore. Preferably never unless you are 100% sure there is no balsam in the objective. WD 40's volatile components will dissolve it. Lomo objectives, with their classic seized rings are very vulnerable to that.

AO, iris objectives from the era of yours, seldom have the problem of seized collars but I have come across a few. Mostly, they have been correction collar objectives and those are harder to fix from the outside than iris collars. There is one old thread on this forum where the poster did not follow instructions and fouled his objective(s). Feeling somewhat responsible because the instructions came from me, I had him send them to me and I cleaned them up. I'm a little hesitant now to recommend this method but with an iris equipped objective, the opportunity for lubricant entry to the optical parts is much lower. Please note the word : STOP

Firstly, since there are many light oils out there and I only know about those that I have used, probably stick to what I have used if you are going to be housing the objective at all. If it is never going to be housed, you are probably alright with many others but that is your call. Any gassing off, needs to be able to go away.

I use Nye PP269 oil. The bottle can be obtained with a thin needle like applicator. Using a needle as an applicator works to release a small drop too. Holding the objective horizontally, slide the collar as far to the thread end of the objective as possible and let one drop into the seam between the bottom of the collar and the front objective housing and let it run into it with gravity. Do the same at the top, while shifting the pressure on the collar away from the threads. Wipe off any clinging to the outside of the collar and barrel and then work the collar back and forth by holding the collar between the crook of your thumb and the crook of your index finger and the base of the objective with the other hand. This pretty much surrounds the objective with the heat of your hand, warming it and facilitates the miscing of the lubricants. 5 minutes should be enough. Most of the time, this will improve the movement of the collar considerably. If it is not enough, use 2 more drops. If there is no improvement after a total of 4 drops. STOP. There is likely a more serious problem and the objective should be taken apart for a more thorough look.


The first thing is. You only use a tiny amount of lubricant at a time, incrementally, and you stop, if no results are

Timor
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Re: Possible to lubricate iris-equipped objectives?

#9 Post by Timor » Mon Mar 11, 2019 4:09 pm

Thanks PeteM for the link, and Apochronaut for the detailed reply. Very useful information for me and I'm sure for many others.
Good to know that the careful use of oil is not necessarly a bad thing.
As my objectives do function, I'm going to try them on the scope and see how I get on with them in actual use. If it proves difficult I'll obtain some of the appropriate oil, follow your instructions and try just a very small amount. Better safe than sorry!

Thank you.
Cheers,
Tim

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wporter
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Re: Possible to lubricate iris-equipped objectives?

#10 Post by wporter » Wed Mar 13, 2019 6:27 pm

Just as an addendum to the above posts, I thought a clarification about adding "drops" of oil or solvent to microscope optical parts, such as objectives, might help neophytes get a better picture of exactly how much they might want to add, so as not to overdo it. Words can sometimes get us into trouble!

Below are two images. One is the size of the Nye oil bottle needle, next to a Q-tip cotton swab. The needle is extremely fine, and lends itself to dispensing microliter amounts of lube.

Next is an image of two droppers, a standard eye-dropper next to the Nye needle, both in the process of dispensing a drop. You want to go with the Nye-sized drop (maybe even smaller than the one shown), NOT the drop from the eye-dropper.
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Re: Possible to lubricate iris-equipped objectives?

#11 Post by MichaelG. » Wed Mar 13, 2019 8:57 pm

wporter wrote:Just as an addendum to the above posts, I thought a clarification about adding "drops" of oil or solvent to microscope optical parts, such as objectives, might help neophytes get a better picture of exactly how much they might want to add, so as not to overdo it. Words can sometimes get us into trouble!

Below are two images. ...
Nicely done

MichaelG.
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Timor
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Re: Possible to lubricate iris-equipped objectives?

#12 Post by Timor » Wed Mar 13, 2019 9:50 pm

Yes, useful information!
(Very useful considering the price of Nye oil here in the UK)
Tim

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Re: Possible to lubricate iris-equipped objectives?

#13 Post by Timor » Thu Apr 25, 2019 10:20 am

Just a quick update for anyone who has the same problem:
In the end I decided to risk using oil. I basically followed apochronaut's method and applied one small drop of oil to top and bottom of collar, and worked it back and forward. Difficult to judge the amount of oil, but using a needle helped keep it to a minimum.
Anyway, after 5 minutes or so it worked perfectly and a month later it's still smooth and there's no sign of contamination of the optics.
So thanks again for everyone's suggestions.

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Re: Possible to lubricate iris-equipped objectives?

#14 Post by PeteM » Thu Apr 25, 2019 1:12 pm

Thanks, Timor, for sharing what worked.

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Re: Possible to lubricate iris-equipped objectives?

#15 Post by Hobbyst46 » Fri Apr 26, 2019 10:02 am

Many tips from experts on this forum are great. I purchased a Standard nosepiece turret. Upon arrival, I noticed friction during rotation, not really smooth rotation. The nosepiece is based on a greased ball bearing. Disassembly can be painful. So I added a few drops of sewing machine oil, and baked it at about 60C for an hour (without any objective on it, of course; this turret model does not contain a lens). Works nicely now.

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Re: Possible to lubricate iris-equipped objectives?

#16 Post by apochronaut » Fri Apr 26, 2019 11:20 am

I'm pleased that worked out for you. Generally, those little seams can't take very much oil at a time anyway, with the excess flooding the surface awaiting removal. The size of the drop that gets absorbed at any one time, is pretty much self limiting.

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Re: Possible to lubricate iris-equipped objectives?

#17 Post by mrsonchus » Fri Apr 26, 2019 12:54 pm

Hi, I oiled (very carefully & sparingly as advised) the coverslip-compensation collar on my x70 last night and it has become nice and smooth and is now much easier to use accurately whilst viewing through eyepieces on my Orthoplan - so thanks for the excellent advice!
John B

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Re: Possible to lubricate iris-equipped objectives?

#18 Post by viktor j nilsson » Fri Apr 26, 2019 2:17 pm

apochronaut wrote:I'm pleased that worked out for you. Generally, those little seams can't take very much oil at a time anyway, with the excess flooding the surface awaiting removal. The size of the drop that gets absorbed at any one time, is pretty much self limiting.
Glad to hear you say that. I re-applied oil to a Nikon Fluor 40x 0.85 correction ring a while ago. I was a little bit rushed and didn't use a very precise applicator, so I definitely applied a bit more than I should have. It's working fine though, so far, and I hope it stays that way.

Edit: although I now realize that you were talking about a nosepiece. Anyway, I'm hoping the I can get away with it this time.

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