In article <3385D1DC.7256@aed.org.nospam>, bharris@aed.org says...

>I have inherited two old non-AI Nikon lenses - a 50mm f2 and a 28mm
>f3.5. Both have moderate -to-severe fungus so I decided to use this as
>an opportunity to clean them myself. I had great success with the 50mm -
>it is now as clean as it can be (the coating suffered a bit, but it is
>quite useable) and the once-locked focusing threads now work great.
>
>I am stuck on the 28mm, however, and I don't want to proceed without
>some info. The rear lens assemblies are no problem; I have removed all
>until the diaphragm. The very front element also came off easily. But
>where to go from here to remove the remaining front lens elements? I
>need to get to the very inner element, just forward of the diaphragm;
>it's badly clouded.
>
>It looks like my choices are to remove a flat retaining ring holding in
>the 2nd element - assuming I can find/create a rubber ring wrench to get
>in there without damaging the element. It's a tight fit. I would rather
>do as I did with the 50mm and remove the entire front lens assembly by
>unscrewing the outer filter ring (where the cap snaps into, and where
>filters screw into). But it won't budge with moderate force, and I don't
>want to break anything. Could anyone tell me if this is possible? I also
>want to clean/lube the helical threads, and I can't see a way of geting
>to them without removing the outer assembly and then the focusing ring.
>
>Thanks - I really don't want to give up now, and I don't have a
>relationship with a local repair shop. Any help would be appreciated.
>
>Bret Harris
>bharris@aed.org (note: remove the "nospam" in the reply-to address)

Nikkors MF lenses are very well made, but it amazes me how many variations
are used in construction, though they all look like they are similar. Try
to find a very small screw hole in the side of the front barrel (this
screw releases the outer front shell, allowing it to unscrew). If there is
no screw hole visible, remove the three screws in the silver "grip" ring
(this allows the lens to be focused closer than normal, and may reveal a
hidden screw hole in the front barrel exterior). If cleaning the rear
of the element ahead of the diaphram is all you need to do, it may be
best to clean it through the open diaphragm (rather than further
disassembling the lens...). Uh, g o o d l u c k . . . . ! ;-)
"Hope This Helps", "Bob Neuman", David Ruether
http://www.fcinet.com/ruether