How to get non-AI Nikkors converted?

[RonVol]

This is another somewhat elegant solution.
In this case on a UD-NIKKOR 20mm f/3.5.
I guess that not all lenses can be converted in this way.

[RonVol]

.............and this is what the modification above looks like on the following cameras: D610, F3 and an F4.

[Erik Lund]

That 105 is just perfectly done!

[Roland Vink]

The 105 looks amazing. No screw holes from the aperture, the AI and EE-servo tabs look perfect, I wonder how it was done?
Is that a join line below the scalloped grip? Maybe the entire lower part of the aperture ring was cut off and new AI part was fabricated and glued on ...?

The AI conversion for the 20mm UD is good, and reversible. It works for this model because the aperture ring is very thin, not possible on other models with a thicker ring...

[RonVol]

I wonder how it was done?
Is that a join line below the scalloped grip? Maybe the entire lower part of the aperture ring was cut off and new AI part was fabricated and glued on ...?

It looks to me like the original ring has been turned to a parallel diameter.
Then a new ring is made and fitted to the original with what might be a shrink-type fit. The new ring is heated slightly causing it to expand and then allowed to cool over the existing ring.
The other option would be for the mating diameters to be machined to close-clearance tolerances and then assembled with some sort of retaining compound like LOCTITE 601.
I like the second option better, less chance of crushing the existing ring.

[Erik Lund]

Well if it was done correctly it's Silver soldering or brazing, very difficult but strong and as good as the original, even stronger.

The other option is two component Epoxy, acceptable but not good at impact resistance,,,

[richardHaw]

I have always thought that Oscar was Swiss

[Matthew Currie]

That 105 is certainly a nice job.

The other one reminds me a bit of a different solution I did long long ago.  In about 1970 I bought a cheap Nikon mount 200 that had no meter coupling at all.  For that one, to use on my old Photomic F,  I made a similar ring with a meter claw on it.  Since there were not even any claw holes in the aperture ring, the added ring was clamped at the bottom with a screw.  A lot can be done with a good piece of aluminum.

[PeterN]

just wanted to say: what a wonderful and informative thread.

[BW]

I got this little beauty in the mail today, but I was not aware it wasn't AI-converted. How slim are the chance that I could get the AI conversion kit no. 39 at eBay? I am not the dremel-type

[Bjørn Rørslett]

Chances are very slim.

Erik [Lund] can do it for you, but not for free. Shipping the lens back and forth adds to the costs too. I'd bite the bullet and get an properly AI'd lens to replace the one you just bought.

[BW]

Ok. Note to self; read add, before buy I have a metal workshop at work. Maybe the guys there could help me out.

[Roland Vink]

I got this little beauty in the mail today, but I was not aware it wasn't AI-converted. How slim are the chance that I could get the AI conversion kit no. 39 at eBay? I am not the dremel-type

While some AI kits for other lens models are still available, I have never seen one for any of the pre-AI 105/2.5 models. Your options are the dremel, or trade it for another which is already AI. The AI 105/2.5 has the same optics, better coatings, same long focus throw and same nicely curved aperture blades - that would be my first choice.

[BW]

Thanks for the tip! The only thing that has to be removed is on the aperture ring, from where I mount the lens, to f11 and 1/3? Or am I missing something?

[Peter]

This is how I hacked mine with a file by looking at a P with an Ai mount for location at what point to stop. Or send it off to to John White at http://www.aiconversions.com/.
The first one I did I screwed up and over cut it between f32 and f22 and not f11 because I wasn't paying attention I had to install a stop to the aperture ring, the second one I did right..
This is a great lens although I like the Ais 105 the P still comes with me, they are built like Hand Grenades.
I love 105 lenses these old non Ai lenses are to be had at a decent prices still. The hood is needed during the day.
I have two P one K and an Ais I have not tried the Sonnar-type 105. The image at the bottom was taken with My D700 and the same lens you have.