Nikkor home made AI conversion question

[Eagle Blue]

I've knowna good while about home grinding of the aperture ring to convert the pre-AI Nikkors. And right now I happen to have a 28mm f/2 where someboddy did an excellent job of it. Certainly they had to have used a mill and not just a file. And I happen to have a Nikkormat FT3 where this lens actually works. But, the edge of hte grind just barelycatches the flip-up stop on the camera dial. As we know on the factory AI lenses, this area of the aperture dial protrudes a bit to make a surer catch of the camera mechanism than the hoe-ground dials do.
So my question: is this home grinding a hit-or miss proposition where ordinary wear or looseness can cause failure. It obviously works on my 2 items, one being a Nikkormat. But how well can is be trusted on an F2A? Thank you.

PS I can spell better than this, but on this little laptop its more than my eyes can handle to place the cursor in the right place to make edits.

 

[Willyekerslike]

As a user and collector of pre ai Nikon lenses I shudder when I hear this topic being aird. There a plenty of ai and ais lenses out there without ruining these fine old lenses. A factory conversion is one thing but grinding down and then removing the 'bunny ears' is something that seems to have become a bit of a fashion. Please just get an ai or ais lens and leave the pre ai lenses to old farts like me who appreciate them as they are.

Regards....lW

 

[BrianVS]

Mora Camera (long gone) converted my Nikkor-UD 20mm F3.5 some 25 years ago, did not have an Ai conversion kit for this lens. (He had the kits for my 300/4.5 Nikkor-H, 50/1.4 Nikkor-SC, and 28/2 Nikkor)

On the 20/3.5 - just looked at it closely, He added a piece of metal to rise about the aperture ring to catch the Ai index ring of my Nikon F2A and F2AS. The metal is curved to the radius of the aperture ring, and is screwed in. The Bunny Ears are in place for my older cameras. This lens has served me well over the last quarter century, no need to replace it. I would not consider it a collectible- I have many non-Ai lenses that I would not convert, but great users like this one- no problem in my mind.

As an alternative- you could look for a "for repair" lens, or "as-is", "Butt-Ugly" of the same series as yours that had the Ai ring added, do a swap. I did that for my 135/2.8 Nikkor-Q.

 

[MartinCrabtree]

John White converts cheap and does a great job. Why butcher when it's that easy?

Click here.

 

[darkroommike]

As others have said, if a lens is collectible or desirable leave it alone, for all the other lenses...yes, some lenses requite that the bit of lens mount left after the conversion be built up in some way to better engage the AI "feeler". I have seen cobbled up versions with epoxy and bits of metal or plastic glued on, better ones done with a bit of metal mounted and screwed on. Original AI conversion kits get harder to find but some are still available, I think that's always the option to investigate first. I got one from Jimmy Koh for my K-type 50mm/1.4 and it was both cheap and easy to install. I kept the pre-AI ring and bits if I ever need to un-convert it. BTW I prefer the term pre-AI to non-AI for earlier lenses since there are some current lenses without an AI coupler.

 

[RalphLambrecht]

John White converts cheap and does a great job. Why butcher when it's that easy?

Click here.

he did a great job on three of my lenses! highly recommended

 

[Eagle Blue]

Thank you for these replies. But I see my question may be misunderstood. I have no intention of having my remaining old style lenses converted. My question is how dependably the edge of the grind catches the finger on an F2A. Since the back edge of the aperture ring on the factory AI lenses protrudes more than it does on the old style lenses, it can get a better or surer "catch" of the camera's feeler. For instance, if the feeler finger on any dp-11 finder may possibly have a bit of play in it, is it possible that the edge of a ground-down AI my not catch the feeler at all, and just go over the top of it and not index at all? Or possibly just bind with it at some point. As I've stated, the edge JUST BARELY catches the flip up lever on a Nikkormat FT3, Ayd less at all and it would just go right over it. So by now my question should be obvious. Even in these fine cameras, there's always imperfect tolerances of such small increments

 

[BrianShaw]

BrianVS and darkroommike mentioned your solution. Add more material to get reliable connection.

 

[John Koehrer]

What it sounds like to me is your concern that the finger may slip onto the ring itself rather then engaging at the groove..
You could sacrifice a bunny ear prong and put it next to the notch, remove the ears, no harm, no foul except to collectors.
I'd drill & tap the ring so the part is attached like the original. You can do this with a pin vise, drill & tap