Help! A messed up LTM Jupiter-11 reassembly

tho60

tho60

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Dear Buddies,

I am forced to ask your help. For a long while I intend to relube my LTM Jupiter-11 lens, but I procrastinated to do it till Friday.

I have managed to disassembly the lens; it differs from the Kiev version significantly. Of course, I made notes and found scratched numbers and alignment lines inside.🙁 There are four helicoids which must be connected correctly in order to work. This was a bad surprise, the system is much more complex than Jupiter-9’one. The optical block cannot be screwed in; it is fastened to the inner helix with two screws. Although I observed the positions of the helicoids and took notes, these proved insufficient during reassembly. I got muddled up.:bang:

But this is not the biggest problem. Like in the Jupiter-9, there are four guide pins in slots which transform the rotating movement into straight one. Having relubed the lens and installed the guide pins I could not turn the focus ring anymore. There is too much force awakening in the slots preventing the alternation.

I used Molykote YM-103 grease which has worked so far in my relubing projects, including J-9s.

Have you ever relubed an LTM Jupiter-11? Could you help me- I trust your advices.🙁
 
batterytypehah! said:
This is where it really sux that Brian Sweeney has left RFF.

Just giving this a bump.

I assume you're already aware of the guide on the Kiev survival site.
Click to expand...

I cannot understand the reason of your comment perfectly, but I assure you that I did not have any malignancy.

The Kiev mount J-11 does not have in common with LTM ones, except of their optical block.

I have asked for help of RFF community because I did not find any other solution, e.g. websites.

Any remarks will be apprecciated.
 
I'm sorry, I don't understand what you mean. I was trying to help, that's all. You didn't say if you already have the Kiev survival instructions or not.

"Giving a bump" means that I added a response to your post so that this thread will appear as active, that means, it's visible on the first page and therefore much more likely to be seen by others.

Lastly, Brian Sweeney would have been the person to ask but unfortunately for us, he left this forum a few weeks ago.
 
batterytypehah! said:
I'm sorry, I don't understand what you mean. I was trying to help, that's all. You didn't say if you already have the Kiev survival instructions or not.

"Giving a bump" means that I added a response to your post so that this thread will appear as active, that means, it's visible on the first page and therefore much more likely to be seen by others.

Lastly, Brian Sweeney would have been the person to ask but unfortunately for us, he left this forum a few weeks ago.
Click to expand...

I am sorry, I believed that you considered my post as a hoax. I apologize and I would not hurt you.
 
Look, we're just trying to help. There's no reason to be annoyed. I understand that English is not your first language but that's true for a lot of people on this forum, but they still manage to be civil. You're not going to get much help otherwise.
 
I took my LTM Jupiter 11 apart yesterday to do the same relube as you. I did eventually get it back together and running. I did take some photos with my iPhone as I proceeded and that helped a lot when it came to reassemble.
Is yours stuck completely or just very stiff?
Can you rotate the focus between the end stop tabs and do the screws go up and down the slots from end to end? If they don't then you have to keep trying other starts on the multi start helicoid until it works.
 
I had to take my Jupiter 11 apart again today, as I had not got the rangefinder calibration correct (I only checked the lens on my mirrorless Live View Ricoh GXR A12 Mount yesterday). Anyway, I have now found out what I did wrong yesterday and now the rangefinder infinity is correct according to my FED RF camera, and infinity focus stop and scale marking is correct on my Ricoh GXR.
Watch you do not over tighten the 4 screws that guide in the slots. Try slackening them a little and see if you can turn the focus. A dab of light grease there helps too. I still find my Jupiter 11 focus quite tight, but very smooth now.
I have plenty of photos of the work now, I will sort them out and may publish them if it helps.
 
Braeside said:
I took my LTM Jupiter 11 apart yesterday to do the same relube as you. I did eventually get it back together and running. I did take some photos with my iPhone as I proceeded and that helped a lot when it came to reassemble.
Is yours stuck completely or just very stiff?
Can you rotate the focus between the end stop tabs and do the screws go up and down the slots from end to end? If they don't then you have to keep trying other starts on the multi start helicoid until it works.
Click to expand...

No, I cannot rotate the focus ring at all after installing the guide pin. Before doing this I can turn it. As I remember, there were only one reasonable position for installing the pins next to the RF tab, i.e the pins must go past a little of the slots when the helix is screwed fully home. However, I could be wrong.

Unfortunately, my quota exceeded so I cannot upload pictures to demonstrate the actual situation.
 
tho60 said:
No, I cannot rotate the focus ring at all after installing the guide pin. Before doing this I can turn it. As I remember, there were only one reasonable position for installing the pins next to the RF tab, i.e the pins must go past a little of the slots when the helix is screwed fully home. However, I could be wrong.

Unfortunately, my quota exceeded so I cannot upload pictures to demonstrate the actual situation.
Click to expand...

I took my Jupiter apart again today to take more photos which may help you:

For the benefit of those who have not taken a Jupiter 11 LTM apart before:

Unscrew the front of the lens from the rear part, this will leave you with the front with the optics and the rear with the focus/RF parts. You may need a rubber grip or strap to untwist it if it is stiff (CCW).

This is the rear part after removal:
IMG_1818.jpg


Now slacked the 3 grub screws on the focus scale ring and slide it off.

Leaving you this:
IMG_1819.jpg


Now remove the 2 tiny set screws from the mount (the outer shiny part with Made in USSR on). Don't lose those 2 screws, put them some place safe.

You now have to unscrew the mount from the rest, CCW, again may need a strong grip or strap wrench.

You will now have:
IMG_1820.jpg


I strongly suggest you photograph things before further dismantling to clean and lubricate, so that you don't forget how it was set up. Been there, done that.

This is the infinity position:

IMG_1821.jpg


This is the close focus position:

IMG_1822.jpg



Another shot of the infinity setting:
IMG_1823.jpg


Checking the infinity RF setting is correct is best done by mounting the mount tube on a RF camera and checking the RF patch is OK at infinity. It is possible to reassemble things so that the RF is not correct as I discovered.

IMG_1813.jpg


More later, but I wanted to get these photos up to help the OP.
 
thanks

thanks

Braeside said:
Any news Tho60?
Click to expand...

Hello!

I apologize for the late answer, but I was ill last week.

Many thanks for your pictures, they were very helpful. However, my LTM Jupiter-11 belongs to an other type. The optical block cannot be screved in or out. It is fitted with two screws to a corksrew-like or bit-like element which is connected to the innest helix.

My J-11 is made in 1958, I suppose yours is a later model.
 
Sorry to hear you have been ill.
I recently had similar problems with a Jupiter 9 lens. - although I had correctly reassembled it, it was almost impossible to move when the guide screws were fitted. It turned out to be the grease I had used was too thick. I ended up using just a small quantity of a light silicone grease and it works again. May be worth investigating a different grease?
 
grease

grease

Yes, it may. However, Molycote YM-103 is my lightest grease.

There are dry, coating-like lubricants, but I have not used them so far.
 
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