Micro Nikkor 200mm AIs vs AF

[Birna Rørslett]

It's the same story with other Nikkors of that era. The A/M ring is ever so slightly too large thus the screw holding it in position exerts constant pressure and material fatigue cracks will eventually develop. My AF 200/4 Micro broke up after 11 years of not using the A/M ring at all

The next year after the 200 Micro incident, I was climbing ('walking' probably was more correct) the highest mountain in Czech Republic, when my AF 105 mm f/2 DC Nkikkor suddenly snapped in two parts, as the A/M ring fell apart. I had gaffa tape in my backpack and taped the two parts together for the remainder of the trip. AF didn't work of course, and neither did aperture, but I got some photos. Back home, Nikon couldn't repair the lens due to lack of spare parts thus I just threw it away.

I have taped down proactively the AFD 85/1.4 and AFD Micro 60/2.8 Nikkors.

[Hugh_3170]

Are these now unobtainable fragile rings candidates for 3-D printing I wonder? 

If so they could be (slightly) re-dimensioned for corrected internal size and made more robust externally?

I never seen one outside of a lens, so please forgive me as I am just thinking out loud here.

[Birna Rørslett]

The A/M ring is connected to stuff on the inside

[Erik Lund]

Are these now unobtainable fragile rings candidates for 3-D printing I wonder? 

If so they could be (slightly) re-dimensioned for corrected internal size and made more robust externally?

I never seen one outside of a lens, so please forgive me as I am just thinking out loud here.

The material of these M/A rings where updated at some point by Nikon, so lenses that went in for repair/service or are manufactured later have no issues.I have had a large number of lenses with the M/A ring design and never had any issues at all. I have however seen this issue on a few lenses.
Most likely they forgot or omitted glass reinforcement in the early rings,,,

[Øivind Tøien]

The A-M ring on my AF 60mm f/2.8 micro (non-D) developed the crack many years ago, so I took Birna's advice and secured it permanently in manual mode with electrical tape before anything more happened.

[Ilkka Nissilä]

The material of these M/A rings where updated at some point by Nikon, so lenses that went in for repair/service or are manufactured later have no issues.I have had a large number of lenses with the M/A ring design and never had any issues at all. I have however seen this issue on a few lenses.
Most likely they forgot or omitted glass reinforcement in the early rings,,,

I have had and still have a number of those lenses with the sliding M/A switch. I have experienced one such ring cracking (on a 80-200/2.8 D N with tripod collar). Nikon repaired it but the sliding movement was not quite as smooth as the original part (they made modifications to make it more sturdy). Anyway, I have not experienced this fault with my other lenses.

I have not used the 200/4 Micro in autofocus mode often, but 1.5 years ago I needed it to photograph frogs. The AF started to squeak (probably from lack of use in AF mode) but that went away after a bit of time using the lens and hasn't returned. The switch works OK and I love that I can get a bit more distance while still getting narrow compositions.

I am inclined to believe that many of these lenses will continue to work fine while some break. Since it's a mechanical system in principle it should be repairable even if original parts are not available.