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Ihmemies
Tinkerer
Username: Ihmemies
Post Number: 1
Registered: 07-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, July 16, 2011 - 06:28 am: | 
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So I have this pre-ai (K) Nikkor 135mm f/2 lens which felt like it's full of sand. I opened it up (and marked the starting places for helicoids of course) and it looks like this:
http://hakkarainen.kuvat.fi/tempo/spam/135_lol.jpg (not cleaned yet)
Big fat helicoids, which probably need some kind of lighter grease if I want the focus to move at all. Automotive shops probably don't sell anything good, and most are mineral oil based anyways. Maybe bike shops sell some nice synthetic greases? Micro-tools europe sells those very expensive greases. I suppose the 8ml jars last a lifetime of Nikkors, but I don't want to spend 50-100€ for grease...
Does anyone have an idea what kind of grease would be nice for such big helicoids? |
Scott
Tinkerer
Username: Scott
Post Number: 153
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, July 17, 2011 - 09:16 am: |
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I use a colorless synthetic grease, brand name "Super Lube", authorized by the USDA, made by Synco Chemical Corp., which I buy in better hardware stores in east Asia. Minus 45 degrees F to 450F. Medium viscosity. It comes in a plastic tube, and you squeeze it out like toothpaste. For lens helicals, a thin smear is adequate.
In Scandinavia, I would try the tool shops where professional mechanics and machinists buy high-grade tools. A good hardware store or auto parts store will probably have something appropriate. |
Ihmemies
Tinkerer
Username: Ihmemies
Post Number: 2
Registered: 07-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 01, 2011 - 04:49 pm: |
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Out of curiousity I tried out the FC-4 grease sold in ebay.. it's light but it has no dampening properties at all, at least with 135/2 :P Well it was marketed as AF lens helicoid grease so no wonder it doesn't have any dampening with MF lenses :D
I need to try something else later... it's just so annoying to dismantle & put that pre-ai lens together. |
Michael_linn
Tinkerer
Username: Michael_linn
Post Number: 20
Registered: 04-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 01, 2011 - 05:38 pm: |
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I completely agree with Scott.
I have been using SuperLube for probably twelve years now. It has the tremendous temperature range Scott mentions, which means that it stays where you put it. Being synthetic, it does not break down, turn rancid, or turn solid.
Last week I had the occasion to service a thirty year old manual focus lens which had been to the beach. I completely stripped it down and cleaned it with ether (no, I don't smoke!). I reassembled it using SuperLube on the helicals and it is mechanically like new.
An 85 gram tube will probably get you to retirement. |
Old_school
Tinkerer
Username: Old_school
Post Number: 107
Registered: 04-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 02, 2011 - 05:38 am: |
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Moebius, is another supplier of instrument lubes. They are on the expensive side as they are Swiss made. http://www.ofrei.com/page246.html
If the guys have had good results with the SuperLube then go for it. . At any rate, the things to look for are the migrating properties, temperature range, & gassing of the stuff. As if the grease gasses it will accumulate on the internal optics & aperture blades surfaces. Which then of course could damage the coatings & be hard to remove. There use to be Losoid (S/P ?) greases to from Honeywell, I haven't a clue if those are still around or who would still manufacture them. There is also Nye's out of New England, that makes precision lubricants. Along the topic of lubricant, just remember that petroleum may causes plastics to break down. FWIW! |
Cooltouch
Tinkerer
Username: Cooltouch
Post Number: 138
Registered: 01-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 02, 2011 - 10:35 pm: |
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I've been using a dark-gray-colored molybdenum disulfide grease for probably 20 years to lube focusing helicals. Bought a tub of it at an auto parts store because I also use it for things like an engine assembly lube, and come to think of it, I'm pretty sure it's the same tub I bought 20-some years ago.
Honestly I haven't ever thought about outgassing but it has shown no signs of separation in the 20-some years I've owned it.
I'm not necessarily recommending it, just mentioning that this is what I've used. And because it's fairly viscous stuff, I've found just a very light smear of it is adequate. Any more than that and focusing can become rather stiff. |
Glenn
Tinkerer
Username: Glenn
Post Number: 945
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, August 03, 2011 - 07:07 am: |
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The re-greasing of long, large diameter helicals is one area where a read of the original lubrication specifications will allow the original 'feel' of the focus movement to be retained, without longwinded trial and error procedures, when using modern or 'what we have on the shelf' lubricants.
Many up market lens manufactures including Canon and Nikon have specified a procedure that sees all the threads coated in a very thin layer of light grease - this is just to prevent wear and galling between the metal mating surfaces. The actual 'feel' and damping is provided by a number of spots of a much heavier grease, equally spaced around the front and rear circumferences of the helical.
The Jena 180/2.8 and 120 /2.8 become delightful beasts to use when the focus is greased to this procedure, the effect being very long lasting. |
Michael_linn
Tinkerer
Username: Michael_linn
Post Number: 21
Registered: 04-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, August 03, 2011 - 11:49 pm: |
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SuperLube is here for $5.26 if interested:
http://www.micro-tools.com/store/P-21033/3-Oz-Super-Lube-Synthetic-Grease-Multip urpose-Lubricant.aspx |
Ihmemies
Tinkerer
Username: Ihmemies
Post Number: 3
Registered: 07-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, August 05, 2011 - 05:11 am: |
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I doubt Nikon is willing to share any information about the original application of greases in their lenses...
I also think that no repair shops (even the one Nikon uses) in Finland possess such information and are unable to do the regreasing properly even if I sent the lens to them. So trial & error is probably the only way, possibly obtaining similar greases in different viscosity and trying to apply them as Glenn suggested.
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Anyways, I bought a small tube of Super Lube out of curioisuty from local shop and decided to try it out with Ai Nikkor 50/1.2 - the original grease had dried out.
I cleaned the helicoids with q-tips & mineral turpentine. Then I applied the grease in a light film over the male & female helicoids.
Without the optical assembly focusing felt just fine. After inserting the assembly back to helicods & screwing name plate back, the focus doesn't feel that great anymore.
At normal orientation (dof scale pointing up) the focus tightens between 0.6 -> 0.5m. Dof scale pointing down, the focus operates in same fashion.
More interestingly, when dof scale is pointing left, focus progressively tightens from infinity to 0,5m. Turning back focus goes very smoothly!
When dof scale points to right, it's exactly the opposite! Smooth when focusing close, tightens noticeably when focusing back to infinity.
This is very annoying when focus doesn't feel the same in both directions and feel changes depending on lens orientation. Any ideas what might cause such behaviour? :P |
Glenn
Tinkerer
Username: Glenn
Post Number: 946
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, August 05, 2011 - 10:20 am: |
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All the contemporary repair and service manuals from Nikon and Canon contain specific details on lubrication and how to apply the grease to the helical. As to repair shops being able to do the job properly - I can only talk about official Canon service agents both here in the UK and in Japan. In all the places I was in contact with the manufacturers laid down procedures were followed to the letter and the recommended lubricants were used.
The problems with the operation of the focus and 'feel' are most likely due to over packing - you are forcing a lot of grease through the thread helix, and a grease that is not viscous enough to support the two members of the helical rigidly enough. Basically the helical has worn with use and the weight of the optical cell causes the inner helical to move about in the outer member causing extra friction at various points. |
Michael_linn
Tinkerer
Username: Michael_linn
Post Number: 22
Registered: 04-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, August 05, 2011 - 06:54 pm: |
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I think that Glenn is on to it as to the overpacking issue. It sounds as if the weight of the optics, when the lens is focused away from infinity, is exerting leverage which is causing binding.
When I use SuperLube, I never coat the entire helical, but just add some sparingly and at intervals on the helical. I don't think that the type of lube is the problem.
In any case, Nikon is unlikely to be furnishing to anyone the lube that they may have used and recommended in, say, 1968. |
Ihmemies
Tinkerer
Username: Ihmemies
Post Number: 4
Registered: 07-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, August 06, 2011 - 09:22 am: |
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I tried to remove some of the grease from helicoids. It made the focusing tighter but otherwise the same. I'll remove the grease completely and try again with a different plan. There aren't that many parts ( http://hakkarainen.kuvat.fi/tempo/spam2/ai_50_12.jpg ) so I ought get it right... eventually!
Nikon had their own service center in Finland earlier, but they outscored it to another company. From reading local forums I've gotten an impression that they only deal with digital bodies and AF lenses, and the service they offer is mainly switching new parts into cameras & lenses. Of course they may have still the specifications, materials and know-how to work with older cameras & lenses too, but I haven't heard from anyone sending their older gear in for service... and I'm afraid to be the first. |
Old_school
Tinkerer
Username: Old_school
Post Number: 109
Registered: 04-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 09, 2011 - 10:54 am: |
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CT: The gassing issue is not that big of a deal unless you leave the equipment in a hot environment like a black car trunk in the desert on a nice sunny day. But, just a consideration if preparing for extrem heat. In the old days, even before me, they use to change the lube in the equipment to match the environment the gear was heading for operations. I used the similar grease in my mix as you from the automotive, but mixed in a lot of silicon grease.
The Best Mike.... |
