Stiff Focus Helicals on 35mm Lenses

[resummerfield]

Some of my 35mm Nikon lenses have stiff focusing helicals. I don’t know what makes them stiff—age doesn’t seem to matter (all those affected are over 20 years old, but some over 30 are just fine), nor does usage (some I haven’t used in years are just fine), and they’ve all been stored the same. One in particular had become so stiff I quit using it. The obvious answer would be a trip to the factory repair center. But the bill would be more than the lens would be worth. So I tried something.…

By extending the lens to close focus and looking in from the back, I could see a small portion of the entire circumference of the helical. Grease was present, and it didn’t seem dry. But I figured some additional lube might help. So I picked up a hypo and long needle, and loaded it up with a thin clock oil Then very carefully, keeping the needle at the juncture of the helicals, I placed a micro-dot of oil every half-inch or so around the circumference. I probably used no more than one good drop on the entire lens, and I was extremely careful to keep away from the diaphragm blades. Then I ran the focus back and forth to work it in, and left the lens overnight pointed down.

It did help a little. The focus is still much stiffer than normal, but useable. Now I’m looking for suggestions. Should I give it another treatment, or should I leave well enough alone? Or should I "bite the bullet" and have it done right at a repair shop?

 

[David A. Goldfarb]

I'd send them in to be serviced. Helicals usually require a heavy grease, not a light oil. There's probably just 20-odd years of accumulated dust and partially dried lubricant that needs to be flushed out and replaced with fresh grease.

 

[Bruce Appel]

The best solution would be a trip to the shop. That said, what you are doing will work to a degree, as long as you don't get carried away with the oil. I have done something similar with a number of older stiff lenses. After you have put a tiny amount of oil in, work the lens a bunch. Leave it overnight on top of something warm, I use my sattelite reciever, but a tv, computer, anything of that ilk will work. Repeat this step a few times and you may get some more use from the lens before it needs to in to the shop.

 

[John Koehrer]

I've done the same thing only using penetrating oil which seems to soften up the grease a bit. The correct solution would be to disassemble & relube with the proper grease.

 

[srs5694]

You could also try doing the job yourself. Dead Link Removed a site that describes how to do the job for a couple of specific Russian lenses, but I'd expect the same principles should apply to most any lens. (Note: This site seems quite sluggish for me, but it will eventually load.) I wouldn't recommend doing this on any valuable lens, though, at least not unless you're already experienced with this sort of work. You might consider buying a junk lens or two off of eBay to practice on before tackling a lens you care about, even if it's not extraordinarily valuable.

FWIW, I've seen recommendations that the very best lubricant to use when relubing a lens is Nye Fluocarbon Gel 868VL damping grease. The company is located at http://www.nyelubricants.com. I don't know if they sell small quantities directly, though, or where to get small quantities if they don't sell directly. I've also heard that bicycle grease works well, but I don't have a specific product name in my notes.

FWIW, I've got a couple of stiff lenses that I've been meaning to relube, but I've not yet done the job myself -- I've just got a small collection of notes and printouts. Thus, I hope I don't lead anybody astray!

 

[David A. Goldfarb]

If you want to try it yourself, be sure you know how to thread the helical back together and get the aperture pins back where they are supposed to be before you start. Manual aperture lenses aren't so difficult, but beyond that, I send mine out.

 

[John Koehrer]

RE: David Goldfarbs note about the helical since there are usually 6-8 threads in a focusing helical there's a real good possibility the lens isn't going back together correctly on the first attempt.
In most if not all better quality lenses there is also a fine thread used for adjusting fine focus. You can't incorrectly assemble the fine thread, but may not set focus correctly. It can be a tedious process.

 

[David A. Goldfarb]

One thing you can do about that is to remove the helical slowly and as the inner tube is about ready to come out, mark both of them with a marker or a pencil so you can line it up easily when it's time to reassemble.

 

[resummerfield]

Thanks for all the input! The thought of disassembly and re-assembly (and getting it working properly!) is a bit overwhelming. The general response seemed to suggeset that I should send it out, so I did. Thanks!