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A lighter grease for helicoid lubrication?
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PostPosted: Sat Apr 22, 2017 11:30 am    Post subject: A lighter grease for helicoid lubrication? Reply with quote

I've been using a white lithium + zinc oxide grease for helicoid lubrication on several lens repairs. I don't use a lot - just enough to allow the threads to smoothly turn. It's inexpensive, and works very well for smaller lenses - but I'm finding it has slightly too high viscosity for bigger helicoids or those with many threads.

I'd like to get hold of a suitable lubricant with a viscosity similar to cold vaseline, if that makes sense? Or, alternatively, if there's a way I can lower the viscosity of the white lithium grease by mixing something else into it, that would be fine too (so long as it doesn't separate over time).

I'd be grateful for any recommendations.

Thanks in advance Smile


PostPosted: Sat Apr 22, 2017 11:51 am    Post subject: Reply with quote

I left a wipe of watch oil in the threads of a helicoid, then applied the grease over and it gave me the damping I required. It was recent so I don't know the long term performance yet, but I know another member mixes watch oil with his grease, then applies.


PostPosted: Sat Apr 22, 2017 2:55 pm    Post subject: Reply with quote

Two I'd recommend are http://www.ebay.ca/itm/271194713421 a very high quality Lithium grease with ptfe.
And http://www.ebay.ca/itm/252833910796 with this one being very lightweight, my Rokkor 58/1.2 felt like it was lubed with honey till I tried this stuff, afterwords, a very light feel.


PostPosted: Sat Apr 22, 2017 4:28 pm    Post subject: Reply with quote

What about this stuff?

Click here to see on Ebay


PostPosted: Sat Apr 22, 2017 5:00 pm    Post subject: Reply with quote

Vaseline is too viscous and oil is prone to migration. I suggest you take a look at this thread:

http://forum.mflenses.com/helicoid-lube-question-t74606.html


PostPosted: Sat Apr 22, 2017 6:03 pm    Post subject: Reply with quote

Lightshow wrote:
Two I'd recommend are http://www.ebay.ca/itm/271194713421 a very high quality Lithium grease with ptfe.


+1

Helimax is the way to go. I've been recommending it here for years over on the repairs board.


PostPosted: Sat Apr 22, 2017 9:18 pm    Post subject: Reply with quote

A few weeks ago I bought a cheap CZJ Sonnar 135 / 4 with a slightly fungused front element and a very stiff focusing helicoid. With the front element out, and successfully cleaned, I could see inside the lens and most of the helicoid was visible - so I thought I would try and lower the consistency of the grease by adding a tiny drop of gun oil, which is very light.

My thinking was that grease is a 'soap' with oil in suspension, the oil in the grease provides the lubrication. If after a time the oil has separated out them maybe reintroducing a bit of light oil that would mix readily with the grease base would return to the grease back to something like its original state. We've all tried lighter fuel, and it works - until it evaporates, then the grease base goes back to being a sticky goo. Adding a light oil should be different, it should mix and not evaporate.

I used a syringe and smeared a very small amount of the gun oil around the visible helicoid, then worked the lens for a while to get the oil mixed in. The difference was dramatic, just as it is when lighter fuel is used, and the helicoid freed up nicely. That was about 4 weeks ago, and it's just as good today, even after standing for about a week since I last used it the focus is perfectly smooth and free.
There was no trace of oil on the aperture at all when I got the lens, and there's none after 4 weeks since I added the gun oil, so I'm very pleased with the experiment at this point, although it's perfectly possible the amount I used was too much and there might be oil migrating onto the aperture in the future? But I did this with minimal stripping of the lens, just the removal of the front element. If I have to strip the lens down in the future, so be it, I was prepared for that when I bought it. But at the moment it's perfectly good, for far less work. Very Happy


PostPosted: Sun Apr 23, 2017 12:55 am    Post subject: Reply with quote

If you always use it, the oil may stay in suspension, but if it sits a year it may migrate.


PostPosted: Sun Apr 23, 2017 10:22 am    Post subject: Reply with quote

Lightshow wrote:
If you always use it, the oil may stay in suspension, but if it sits a year it may migrate.


It could do, that's a chance I took. It was just a quick fix that let me try the lens before I stripped it, which I planned to do. But while it's working, I'm not going to bother.


PostPosted: Mon Apr 24, 2017 4:53 pm    Post subject: Reply with quote

That Helimax should be OK.

You need to make sure you use something that is a synthetic base and doesn't migrate. So many greases will migrate and/or outgas, which is HORRIBLE for optics. I work in laser optics, so I know about this stuff. Smile

We actually keep this stuff around here, and it's quite clean. We've put it through many tests for outgassing. It's expensive though:

http://www.apiezon.com/products/vacuum-greases/l-grease


PostPosted: Mon Apr 24, 2017 8:37 pm    Post subject: Reply with quote

But aren't apiezons terribly viscous? My recollection, from the time I worked in the lab, is that when setting glass vacuum valves with L/M mix I always hit both valve and seat with a solid blast from a heat gun before applying the grease.


PostPosted: Mon Apr 24, 2017 10:07 pm    Post subject: Reply with quote

Gardener wrote:
But aren't apiezons terribly viscous? My recollection, from the time I worked in the lab, is that when setting glass vacuum valves with L/M mix I always hit both valve and seat with a solid blast from a heat gun before applying the grease.


The L is a bit thinner than the M. Both are fairly thick but they work really nice on fine threads in my experience. Maybe a bit too thick for fast moving stuff, you may be right.


PostPosted: Tue Apr 25, 2017 6:24 am    Post subject: Reply with quote

Thanks for the great replies, all - greatly appreciated Smile

I think I'll be picking up some of the Helimax, and also some of that light-grade Japanese lubricant.

Does anyone know of a UK or EU supplier for Helimax?


PostPosted: Tue Apr 25, 2017 6:47 am    Post subject: Reply with quote

BigMackCam wrote:
Does anyone know of a UK or EU supplier for Helimax?


No UK supplier that I can find but this is the cheapest option from the states that I can locate:-

http://www.ebay.co.uk/itm/271194713421?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT


PostPosted: Wed Apr 26, 2017 8:32 am    Post subject: Reply with quote

Thanks Smile