Vivitar series 1 28-90 mm jammed focus ring, help!

[inombrable]

Hi everyone,


I have a series 1 zoom Nikon AI fit with a jammed focus ring (bought it like that). I´ve taken apart the whole lens also for cleaning and relubing. The big problem is that i can´t manage to fix the focusing problem. The thread has 17 possibilities and all of them are extremely stiff to be right, i´ve tried without grease, silicone grease and lithium grease but so far all of them feel the same. I have the parts manual and I aligned it according to it but still the focus ring doesn´t move freely.

Any suggestions? I am missing something? Thanks a lot for your help.

[Lloydy]

I've used silicone oil with good results.

But maybe there's slight damage on a thread ? it won't take much to make it stiff, just a small burr on a thread.

[inombrable]

Thanks Lloydy, it doesn´t look or feel like damaged but i will take a closer look again and see if that is the problem.

[inombrable]

Update:

I´ve checked both threads and they look and feel fine to me but still can't put them right, tomorrow i will try to look at them under microscope (but i think that is too much).


Any other ideas ???????

[martinsmith99]

I've used WD40 on threads that are stiff with good success as I have heard that it's slightly abrasive. Try lubing with that a few dozen times without letting it dry, clean it all off and use some silicone.

[Lloydy]

Engineers ( old school engineers ) use lapping paste to mate two parts together, the paste comes in various grades and you put it between the two parts and work them back and forwards through the normal range of movement. It won't remove huge amounts of material, but it shows up and helps reduce the high spots.

If it was my lens, and in bits, I would try a bit of toothpaste on the thread, work the thread and thoroughly wash it off. I've done it on a lens with a high spot on the focusing ring and it helped a lot.