Ai conversion of non-Ai Nikon lens

[James24]

I would like to thank all for replying. Most helpful. I'm currently in email discussion with Marcel on eBay that James24 referenced.

His work looks neat and tidy, and well priced. I'd be interested to hear how you get on if you use him.

 

[ZivcoPhoto]

I bought a 105mm F2.5 P Nikkor new in 1968. I really wanted to keep this lens after I semi retired my first Nikon F and started using F3 HP 15 years ago. I found the same lens on EBay with factory Ai conversion kit so I bought it and put the ring on my lens and sold the lens on eBay after giving it my non Ai ring. When I found identical lens which had factory Ai ring conversion for my original 50mm F1.4 (purchased in the PX in Saigon in 1969) it looked too complex for me to change so I ended up keeping that lens and leaving mine with the non Ai ring. But I also have sent other early lenses out to be AI’d and they came back functional but clearly “hacked”.

 

[Highway 61]

+1 for John White. I have had six lenses converted by him plus I bought a lens from him that had also been converted by him.

The OP's lens has been filed down and Ai'd already. Sounds like a bit too much of metal was filed off, hence the OP's concern about a possible too narrow contact area between the camera coupling dot and the lens coupling flange, and some slipping of the camera coupling dot over the lens coupling flange (if I understand it all correctly) when actuating the lens aperture ring.

I don't see the point of now sending that non-Ai lens to somebody whose purpose is to file them off to Ai' them - even if he works more cleanly and more precisely than the guy who Ai'd the OP's lens. What has been filed off already cannot be re-filed off with, that time, less of metal removed.

From what I guess by reading the opening post, it works. I would advise the OP to use his equipment and spend his money on fillms rather than keeping concerned with this.

I may change my mind with a close-up photo, though, if I saw some butchery prone to break the camera coupling tab, but this isn't what I guess from reading.

 

[Ricoh]

The OP's lens has been filed down and Ai'd already. Sounds like a bit too much of metal was filed off, hence the OP's concern about a possible too narrow contact area between the camera coupling dot and the lens coupling flange, and some slipping of the camera coupling dot over the lens coupling flange (if I understand it all correctly) when actuating the lens aperture ring.

I don't see the point of now sending that non-Ai lens to somebody whose purpose is to file them off to Ai' them - even if he works more cleanly and more precisely than the guy who Ai'd the OP's lens. What has been filed off already cannot be re-filed off with, that time, less of metal removed.

From what I guess by reading the opening post, it works. I would advise the OP to use his equipment and spend his money on fillms rather than keeping concerned with this.

I may change my mind with a close-up photo, though, if I saw some butchery prone to break the camera coupling tab, but this isn't what I guess from reading.

Yes, more or less an accurate summary.
I'm an engineer and always question solutions. Generally speaking if something doesn't look right, it usually isn't. In this case, with marginal engagement, the force per unit area is elevated due to minimal contact. Further, I understand the 'tab' is plastic, and well the rest is obvious.
Film wise I have a fridge full, but I still can't resist buying more, especially the more obscure, eg just purchased some FPP Retrochrome.

 

[Highway 61]

Yes, more or less an accurate summary.
I'm an engineer and always question solutions. Generally speaking if something doesn't look right, it usually isn't. In this case, with marginal engagement, the force per unit area is elevated due to minimal contact. Further, I understand the 'tab' is plastic, and well the rest is obvious.

The tab is plastic indeed but the only very rare examples of broken FM2/FE2 etc tabs which I can think of got broken because of a problem which was the exact contrary of yours (non-Ai lenses mounted nonetheless on the FM2 with the tab forced upwards, or filing-down Ai conversion which had left too much metal behind).

Without a close-up photo, even a basic one taken with a smartphone, it's difficult to answer your question properly without being in the pure speculation field. Couldn't you post one here ?

 

[Ricoh]

The tab is plastic indeed but the only very rare examples of broken FM2/FE2 etc tabs which I can think of got broken because of a problem which was the exact contrary of yours (non-Ai lenses mounted nonetheless on the FM2 with the tab forced upwards, or filing-down Ai conversion which had left too much metal behind).

Without a close-up photo, even a basic one taken with a smartphone, it's difficult to answer your question properly without being in the pure speculation field. Couldn't you post one here ?

Thanks Highway 61.
I do have photos from my iPhone showing the amount of engagement, and I'll try adding them a little later. It's either wrestling with the RFF gallery or more likely hosting them on Flickr.