Here it is. Infinity lock is off. Stop[s are off. The distance ring is pried off and loose.
I've used all the force I can with a rubber sheet.
Maybe vinegar ?
I would not use vinegar because of the risk of causing corrosion to the metal and the inability to flush it entirely if it fails.
BTW I hope you have removed the lens elements so there is only metal to worry about.
I agree with Sonnar Brian that what you have tried already should work, I have never known it to fail.
Which leads me to think that maybe the problem is indeed mechanical - if the lens shows no obvious signs of physical damage as you say, a couple of other possibilities arise, I suppose - just thinking it through as I write........
One is that it may have something to do with the helicoid key - a small usually rectangular piece of metal which is driven up and down in a keyway slot driving the lens in and out as the focus is adjusted. I wonder if there is some way this could have been jammed or if the screw holding it in situ has been driven in too tightly. (a guess) ????
Alternatively, one other thing comes to mind - if there were no grease in the helicoid one further possibility presents itself - corrosion of the threads are preventing movement. (It's a guess but these lenses are so relatively simple in their design it is hard to see what else could go wrong. (I do not presently have an Elmar 50mm any more - I had one but had a look at my old Summitar which has a somewhat similar construction. The thing about these types of lenses is that the rear of the lens and its internals tend to be very exposed to the elements and possible ingress of crap.
One final thought. Assuming all the glass is out of the lens a further thing you might try is to gently (GENTLY!) heat the body of the lens to see if this has an effect either by softening any hardened grease or by breaking the bonds of any corrosion that might be locking it in place. It sounds radical and is so needs come caution and care plus willingness to accept it could be damaging if overdone.
Not sure if there is anything in these threads that helps.
The first is a step by step guide to working on the Nikkor 50mm f3.5 collapsible which is a close cousin to the Elmar and appears to be based on it. There may be some hints in it which help to the extent that they have similar construction. The guy who writes this series of guides is very good and his info is pretty comprehensive and useful. It's not exactly on point but its the best I have found online so far.
What’s up, everybody? I am loving the weather now because Spring is nearly here! Here in Japan, we will celebrate the Spring Equinox next week. I’m sure glad that the seasons come and g…
richardhaw.com
And here is a discussion on what other people have tried to deal with overly stiff helicoids in this lens type.
Great looking lens arrived today with great looking IIIF RD ST. Lens focus stiff: what, if any, lubricant, could I put on threads, albeit in a minute quantity on a Q-tip?
www.photo.net
