Focusing Helicoid: To Lube, or not to Lube?

Discussion in 'Camera Building, Repairs & Modification' started by little-infinity, Jul 20, 2011.

  1. little-infinity

    little-infinity Member

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    This is a followup to an older thread that I posted here in November. Basically the focus was slipping and very stiff (close to being stuck). And infinity was at 5m. It was causing problems because the rear element was interfering with my mirror.

    Well I finally got a chance to look at the lens this week, and the problem was not too hard to find. The focusing ring WAS slipping, AND the helicoid was placed on the wrong thread. All that needed to be done was a quick adjustment to the helicoid and tightening of the screws/washers.

    So while I fixed the actual problem, the lens was still stiff. I figured the grease was old, so I cleaned the helicoids with alcohol and lighter fluid. The lens was pretty much flawless.

    This is where my concern lies. I kinda left it that way and put the lens together and it was smooth, BUT I know better, and the threads will be worn out. I bought multi-purpose lithium grease from Canadian Tire today, and I'm wondering how it will work out.

    Will Lithium grease make the focusing smoother and looser, or should I just leave it unlubed? I know there are better alternatives, but this is all I have at the moment.

    As well, how much grease should I use, and how/where should I apply it? See this image (not mine) for a good reference on what the helicoids on my lens look like. The gold part on the left also slips off so it's actually 3 seperate rings.

    Thank you!
     
  2. Ian C

    Ian C Member

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    For most lenses used at normal temperatures this is the best helicoid lubricant I’ve found.

    http://www.micro-tools.com/store/P-HG-30/Grease-Helical-30-Medium-8ml.aspx


    For lenses used in Arctic temperatures this is a better choice, as it generates less drag, especially in very cold temperatures.

    http://www.micro-tools.com/store/P-HG-10/Grease-Helical-10-Light-8ml.aspx


    I don’t recommend the HG-3000 from Microtools. It generates too much drag for most camera lens applications.

    All three of Microtools HG series helicoid greases are made in Japan for the Japanese optical industry and are the best I’ve found for the purpose of lubricating focusing helicoids.
     
  3. little-infinity

    little-infinity Member

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    Hmm. So lithium grease is a no-no?

    What's the big diff between light and medium? I really like my focus rings really loose for quick adjustment, so will the light work in normal temps too? And how much would I need to apply, and how?

    The old grease was thick and disgusting. Someone else must have tried a botched DIY service because it was so gummed up. They probably put too much and in the wrong places. I want to avoid that.
     
  4. Gerald C Koch

    Gerald C Koch Member

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    Many people use too much grease. It should be used sparingly.
     
  5. little-infinity

    little-infinity Member

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    Ahh. I did some reading and someone did it with an artist's paintbrush (I have plenty of those!) Like only for the grooves, or the whole thing? Should I lube both rings, or just one? I assume one layer on one ring is enough to give enough space between both sets of threads.
     
  6. Leigh B

    Leigh B Member

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    The main characteristic required for helicoid grease is non-migrating.

    It means that the grease does not separate, and stays where you put it. Most greases do not have that characteristic.

    Helicoid grease is designed for use with aluminum. Most greases, including lithium and Lubriplate, are designed for steel.

    The HG30 from Micro Tools would be a good choice.

    That company is the largest supplier of tools and supplies for the camera repair industry.

    Use a very small amount of grease. Put a bit at the beginning of the male threads, where they will mate when you assemble it, and a slight bit more further down. Exercise the helicoid through its full range a number of times to distribute the grease. You should end up with a very thin film evenly distributed along its length, in all threads.

    BTW, when you disassemble the lens, make marks to indicate the exact alignment of the various parts, and re-assemble it correctly. This matters on some lenses, not on others. If it does on yours, and you didn't make the marks, you're in deep kimchi.

    - Leigh
     
    Last edited by a moderator: Jul 20, 2011
  7. lxdude

    lxdude Member

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    Kamsahamnida! :smile:
     
  8. Mike Wilde

    Mike Wilde Member

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    On a more locally available repair grease option...
    I have had good success with using a tiny bit of single touch water faucet mixing cartridge silicone.
    Home Depot sells a little bit of it for about $5. A little of this stuff goes a long way.

    Mine was originally bought becuase of stiff faucets in my home.
    A toothpick worth dabbed onto some old lens threads after freeing them of the dreaded old green grease turned to glue now has them moving very nicely.
     
  9. little-infinity

    little-infinity Member

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    Hmm. Thanks Mike! I'll go check it out.

    As for male threads, I assume that would be the smaller silver ring?
     
  10. Leigh B

    Leigh B Member

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    Yep, the threads on the outside.

    - Leigh
     
  11. little-infinity

    little-infinity Member

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    +update

    On a somewhat unrelated note (I don't feel like starting another thread just yet), I re-assembled the lens just to see if I got the focus right and it seems bang on (at least at infinity). But when rotating the lens towards close focus (between 0.6-0.7m) i hear a click. Okay I thought it could be something loose, but when I turn it back towards infinity, as it passes that very same spot, I hear horrible crunching noise. It didn't take long to realize that a spring was interfering with the rear element. You can see it happening in the pic below.

    It only happens when the depth of field lever thingy is pushed towards the left (when mounted on camera). The tension on the lever pulls the spring right into the path of the rear element when i try to focus it back towards infinity.

    My first thought was that I re-assembled the helicoids incorrectly (and the rear element was pushing too far into the barrel causing the spring to pop in), but the infinity focus is working, so I assume everything else is accurate, and the elements are positioned where they are supposed to be.

    What gives? I plan on disassembling the lens to properly grease, but I would like to know how to fix this as well.
     

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  12. John Koehrer

    John Koehrer Subscriber

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    Looks like the stop down spring. There is usually a groove inside the mount to keep it from popping out like that.
    I use lithium for the helicoids. =-)
     
  13. little-infinity

    little-infinity Member

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    Owch. Yeah I looked for it but it doesn't appear to have such a groove. Here is a better shot of someone else's Minolta 58/1.4. Top-down view of the mount. As you see there is nothing stopping the spring from going into the path of the rear element (bottom right).

    [​IMG]

    If it didn't do this before why on earth would it be doing it now? :blink:
    In any case I want to be certain because overtime the spring will get damaged if I leave it that way.
     
  14. Bob-D659

    Bob-D659 Member

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    Your link to tripod didn't work, and you do have your lens assembled wrong. I'd guess that blurry ridge to the right of the spring should be rotated to the left to keep the spring in place.
     
  15. little-infinity

    little-infinity Member

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    oh shoot. I think the tripod site doesn't like hotlinks. you might want to copy the link URL instead, I can't seem to edit the post to embed the image. Sorry!

    I'll take another look at it, but I dunno how I could go wrong, it only fits one way on this lens anyway. I'll try to get a clearer picture, but my phone doesn't do macro.
     
  16. little-infinity

    little-infinity Member

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    Forgive the double post, but here is a clearer image of my own lens. I looked for any place where it would be guarded from going in but i found nothing. A member pointed out that the spring should be curved instead of straight though.

    [​IMG]

    Anyways I'll leave it at that for now and will update on how the greasing goes later.
     
  17. John Koehrer

    John Koehrer Subscriber

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    It's been a while(what hasn't?) But if there's tension on the spring why isn't the spring pulling the actuator towards the fixed post?
     
  18. Leigh B

    Leigh B Member

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    Because the ring is already as far counter-clockwise as it can go. The actuation direction is clockwise, not counter-clockwise (anti-clockwise for our British friends).

    I think the spring should attach to the vertical black tang by his right thumb in the last photo.

    That tang and its base move clockwise to close the aperture when the camera fires. The aperture ring, at the screw end of the spring, moves as far as the aperture ring setting will allow. That's the reason for the spring.

    When engaged in that position I believe it will be completely clear of the rear lens element.

    When the lens is in its non-released state, as viewed here, the tang pushes the aperture control ring to the full open position (counter-clockwise).

    - Leigh
     
    Last edited by a moderator: Jul 26, 2011
  19. John Koehrer

    John Koehrer Subscriber

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    Actually, The spring is connected properly and the stop down lever should be as far CW as possible.
    The tab has nothing to do with the spring.
    There is a small black light baffle held on by three screws visible from the back of the mount. This should have a raised edge
    (~2mm) on the inside of the mount and the spring rides against it.

    Has this baffle been installed upside down giving a smooth surface inside and a raised edge outside?
     
  20. little-infinity

    little-infinity Member

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    Bingo.

    WOW I feel like a fool. Thank you very much for pointing it out. And now my lens is all good to go.

    Thanks everyone for the help! :smile:
     
  21. Nicholas Lindan

    Nicholas Lindan Advertiser Advertiser

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    "Damping grease" is the proper name for what you are looking for
    http://www.nyelubricants.com/lubenotes/LN_Damping_Grease-03-1.pdf There not being a large base of US lens makers most of the literature on selecting lens helicoid grease is in Japanese and Chinese. But the greases are the same as the US product.

    High vacuum grease is another alternative - though not exactly a commodity item.It won't migrate no matter what - really great stuff and a lot easier to clean up after compared to some of the stickier damping greases.
    http://www.ellsworth.com/display/productdetail.html?productid=403

    The 'faucet grease' sounds like it belongs in the damping grease camp. Microtools is repacking either Nye or Corning [or Gongzhu Optical Product and Tractor Works] grease. I didn't look at the pricing differentials but a small amount of the stuff will last you a lifetime.

    Any sort of household grease will separate and you will get oil all over the inside of the lens.
     
    Last edited by a moderator: Jul 27, 2011
  22. John Koehrer

    John Koehrer Subscriber

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    To be honest I had to peek at one I've got here. :smile: Sure as hell wasn't from memory.