Dead Jupiter

siracusa

siracusa

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Aug 24, 2010
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Fresh from the success of making my Jupiter 3 focus correctly I decided to mend a Jupiter 8 I was given some time ago as a basket case.
Focusing on the J8 (a black 1970s version) was slightly stiff and it clearly needed lubicrating. I mounted it to test it but barely took more than a dozen images with it until I put it on the camera one day only for it to seize after five minutes in much the way a car engine might seize in the absence of oil. The focus ring is stuck at 1.7m and will not budge. I've opened the J8 up following the instructions that can be found on the net, and can see the remains of some grease around the top of the helicoid threads, but I cannot remove the helicoid. Stuck as if welded in place. I don't want to force it and ruin any threads. I'm guessing that penetrating oil would be a bad idea. Any ideas on how I might attempt to remove a seized helicoid?
FWIW my guess is that it's probably unrepairable. I guess the metal has become deformed from the extra force applied to turn the stiff focus ring. I was gentle with the lens and have barely used it but I can't vouch for how rough the previous owner might have been. The lens came free for a reason, after all. Still, I might as well try in case it can be salvaged.
Thanks in advance for any suggestions.
 
Perhaps Naptha (lighter fluid) SPARINGLY applied very carefully a drop at a time and allowed to soak in might loosen the gummed up grease. I'm going on recommendations from others here and elsewhere. But if I'm wildly off base, please someone let him/me know. Hope this helps.
 
How goes it... been about an hour or so...
Did warming the lens up help loosen it?
 
Gently blowing warm air with hair blower is better method than wrapping lens in steamed towels. Just don't melt whole thing :)

p.s. Seeing your thread I did remember I have early silver J8 in a bad shape lying around, fetched it out and cleaned here and there. Focusing tab is broken off, front element is generously covered with small scratches (and these aren't cleaning marks!) and has a bit of fungus behind it, focus ring misses set crew or two but does the job. Probably I've got 50cm Softar :)
 
Funny you should ask, DNG, I have tried - with a hairdryer, great minds clearly think alike btgc ;) - but with no joy I'm afraid. There is now lighter fluid slowly working into the threads. I feel like I am bonding with this lens under conditions of shared adversity. The feeling of wanting to throw it out of the window has not yet arrived. I like your story of the newly rediscovered Softar, btgc. A rare lens indeed!
 
Before you throw it out the window just grip that sucker & twist for all it's worth. Those threads are stronger than you might think. My bet is it's misthreaded to seize up on you like that. Good luck with it.
 
I have found Xylene works best.

If you can remove all of the glass drop it in a closable glass container and let it soak for a day or two..

I have freed up a couple of frozen hellicoids from the Pax cameras this way. You may have to let it soak longer depending on how dry the old grease is..
 
I thought I'd post a quick update. After leaving the lighter fluid to soak into the threads overnight it is still stuck fast. Perhaps this wasn't long enough so I shall try again and leave it a couple of days to soak through. If I still have no luck I'll assume the helicoid is misthreaded or the metal deformed and try force-perhaps a strap wrench, which should give me purchase to turn it while the rubber will have enough give not to cause too much further damage. I wouldn't do this to a lens except that this one was free, and a basket case, so there's nothing to lose. And if that fails I'll keep it for parts, should I ever need them.
 
If you can't unscrew the helicoid, try screwing it in a bit first. Often, if a thread is seized it can be freed by repeatedly moving it back and forth over what movement there is. However, based on the design of this lens I'm more than a bit surprised it could seize so solid in one place. Are you sure one of the stop-screws hasn't come adrift and jammed it, for instance?

If you're sure it is seized due to gummed grease or whatever, take the optics module out and soak the mount in diesel fuel or lighter petrol for a few days. Apply some heat with a hairdryer and try again. Obviously, since diesel/petrol is flammable you'll need to take care how you heat it and how much!
 
Thanks Wolves. Yes, the optics block is out and the lens is disassembled save for the seized helicoid that I can't remove. I tried heat once but will try again after it has soaked further for a couple of days. I suspect the metal is deformed or that it is misthreaded - there is no other logical reason for it to have seized fast. Even if the grease had gummed I'd expect a little give or movement, but it is as though welded into place. Thanks again, and to all posters for the helpful suggestions I have received.
 
If a thread is completely dry, it is possible (particularly with aluminium) for it to "pick up", where the parts literally weld themselves together over a very small area. I think this is unlikely to be the problem if there is even a trace of old dry grease, but if it is, a soaking in penetrating oil followed by brute force is the only option.

If the helical is misthreaded, with careful measurement you could probably detect some tilt between the inner and outer. Both my Jupiter 12s had damaged helicals, but I think the '8' is probably a bit stronger.
 
You might have to try the old Isolette/Speedex trick. Get a bottle of at least 91% alcohol. Put the lens in a container big enough to allow you to fill it all the way up w/ the alcohol, so that the lens is completely submerged. Then forget about it for a day or two. I had a stuck helical on an Isolette (one of many) and had tried everything before doing this w/ the entire shutter/lens assy. After two days it unscrewed in my hand w/ no pressure at all. I was pretty shocked. The alcohol did no damage to anything, and after letting it all evaporate out for a few days, I simply wiped it off the glass w/ lens tissue and lens cleaning fluid, and blew off the shutter w/ canned air. Keep in mind that if you do this you will have to completely disassemble the lens afterwards to clean things, but that's not that difficult on a J-8. Penetrating oil might also work, but would be more difficult to clean off.
 
The helicoid is free!!! Hooray.
Okay, I'm going to start with the fisherman's yarn about what happened, and then I am going to say how I really freed it.
In version 1, not having any 92% alcohol, I stuck it in some 42% Barbayanni Ouzo that a Greek friend brought me back from her holidays. An hour in that, and it opened.
What really happened: I indeed stood the lens in Ouzo before realising what a waste this was: there's a long distance between 92% alcohol and 42% Ouzo and, apologies to Ouzo lovers, but the Ouzo won't cut it for this job. So I took it out, dried it off and applied brute force. And brute force triumphed.
I do prefer version one of the story and I will be sure to tell this to my friend Katerina who gave me the Ouzo, but the truth is brute force did it.
The helicoids should be regreased and the lens reassembled by tonight. Thanks all for all the tips and pointers along the way - extremely helpful.
 
You made it!
Yes, force works in 90% for me, in Jupiter-3 I have now and several old folders triplets before.
With similar frustraitions as yours.
I think, after dropping some solution between threads it has to be on pause for 24 hours or more. It was recommnded before.
And I'm sure Ouzo, Ricard, Scotch or Stoli appied internaly into your system also might help to apply the force.
Cheers!
 
Cheers Ko.Fe.! After this herculean task, once reassembled, that lens is not coming off my camera for a good while - I'm not sure whether the lens owes me, or whether I owe the lens, but it's not about to get any rest :)
 
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