Manual Nikkor lenses (AI/AIS) become "loose" in the focus ring - why?

[basker]

Per,

I believe that having an accurate diagnosis is the most critical part of a repair. I also agree that an expert overhaul might fix an undiagnosed problem. Your description of the symptom makes me wonder if the slack is between the optical unit and helicoid instead of between the helicoids. If that is the case, how would grease help?

Sam

[Per Inge Oestmoen]

To the OP - If you are not accepting my advice - nothing wrong with that, really - elementary rules of communication require you to say very simple "thank you", coze I spent time try to help you. LZ

Dear Longzoom, of course, your help has absolutely been helpful, as have those of others. I apologize if I have made a different impression, such was not my intent. I am thankful for your comments. There is no doubt that lenses exhibiting these symptoms need service.

[Per Inge Oestmoen]

Per,

I believe that having an accurate diagnosis is the most critical part of a repair. I also agree that an expert overhaul might fix an undiagnosed problem. Your description of the symptom makes me wonder if the slack is between the optical unit and helicoid instead of between the helicoids. If that is the case, how would grease help?

Sam

I also am very much in doubt that grease would remedy the problem, although grease is necessary to ensure proper operation in the long term. Thank you.

[Per Inge Oestmoen]

An alternative and plausible cause is the screws holding the focusing guides in position have started to work loose.

Do get them to a qualified repair shop. If you are located in Oslo, FotoCare is the obvious choice.

Thank you, Bjørn. I have just contacted the repair shop and we have made an agreement to diagnose the problem.

[basker]

Thank you, Bjørn. I have just contacted the repair shop and we have made an agreement to diagnose the problem.

Per,

I would very much appreciate hearing whatever final diagnosis is given by the repair shop.

Thanks,

Sam

[Per Inge Oestmoen]

Per,

I would very much appreciate hearing whatever final diagnosis is given by the repair shop.

Thanks,

Sam

I am also curious to learn what is the actual "affliction" - very much so. I will report back.

Thank you too.