FSU Lens not screwing into certain adapters and cameras

[Ong]

Curious if anyone has experienced this, but I have a I-22 that seems to be very picky into what it screws into. It screws perfectly into my CV LTM-M adapter, as well as well as one no brand adapter.
However on another adapter, or a Canon IVsb it only screws partially before the threads lock up and you can't screw it any further.

The adapters work for every other lens, and every LTM lens besides that one I-22 will screw into the Canon fine.

Am I just screwing things in wrong, or is it the possibility of being a "Hangover at work" lens?

 

[bobby_novatron]

Do you have an old FSU / Commie camera lying around? The quality control on Soviet products was notoriously inconsistent. Maybe try using the lens on a FSU camera and see how well it screws on and whether the register is consistent.

All the best,
Robert

 

[ray*j*gun]

I had that issue with an I22 collapsible and the thread pitch was just not machined very well. As noted above the FSU quality was spotty and can vary from example to example.

 

[farlymac]

It's likely not the same issue of an I-22 not mounting on a FED 2 because of the flange shoulder being too shallow (infinity lock drags on the camera body), but probably just the fact it has a different thread pitch than the adapter you are using. But I'd still check the infinity lock.

PF

 

[goamules]

There were different specs for the threads. And there were different tolerances needed by different cameras. I've had several post-war FSU lenses that are too tight on some cameras from Japan....which have very tight tolerances.

I seriously doubt a country that could make Titanium submarines, Soyouz space vehicles, and dozens of types of supersonic fighters and bombers would have "poor quality control" on a ridiculously simple, relatively large screw thread. Their lenses screwed onto their cameras of the time fine. It's just today, 50 years later, people are trying to fit them to things that they weren't designed to fit.

 

[xayraa33]

I have the same problem with a two post war Industar 10 lenses

They fits fine on a Nicca/Tower Barnack but not on a Leica Barnack camera.

 

[David Hughes]

There are versions of the screw thread according to the maker, one is a hybrid based on a mistake made early on when the Leica thread was being copied. So not only an ex-USSR problem although they always get blamed for it and called clones...

Regards, David

 

[ray*j*gun]

The term clone is about attempts to copy the original Barnack product. Its not limited to FSU products. And if you have ever taken an FSU camera apart or seen it done, you might be shocked as I was. BTW I own 2 Zorkies and a number of FSU lenses so this is not a condemnation.

 

[David Hughes]

The term clone is about attempts to copy the original Barnack product. Its not limited to FSU products. And if you have ever taken an FSU camera apart or seen it done, you might be shocked as I was. BTW I own 2 Zorkies and a number of FSU lenses so this is not a condemnation.

Hi,

It was a comment about how often FED and Zorki versions are called clones when compared to other makers who copied the Leica II. I think that post-war they had moved away from being clones and were then based on the model II Leica.

What really irritates is the fools who call the Zorki 6 or FED 2 clones (especially when selling one) and they are not the only ones just two I glanced at when I looked up from the keyboard.

Regards, David

 

[Ko.Fe.]

I-22 won't even screw on FED-2, but on Zorki. Why? Because Zorki has more clearance of the LTM from the body. Solution, file the infinity lock butt.

 

[Steve M.]

Try a little (a little) bike chain oil on the threads. I've had to do this for some filters that didn't want to screw onto some lenses.

 

[lynnb]

Ong, I had this problem with a J-8. It screwed perfectly well into a Zorki 4 and a Fed 3, but didn't like the IIIc one little bit. Scott at Mainline suggested forcing it to fit the IIIc, given the IIIc's mount thread is harder than the Jupiter's thread. It worked.

BTW a different J-8 had no problem at all mounting on the IIIc (as well as the FSU bodies), so I put it down to sample variation (unless they changed the pitch between the two samples).

 

[Ong]

Thanks for the responses.

For the record, it screws in fine with my Fed3a and almost all my adapters.

It's just the 1 adapter and the Canon IVsb which has this issue. I'll try what you suggested Lyn. Trust Mainline to give us a low tech but effective solution!

 

[tunalegs]

I seriously doubt a country that could make Titanium submarines, Soyouz space vehicles, and dozens of types of supersonic fighters and bombers would have "poor quality control" on a ridiculously simple, relatively large screw thread. Their lenses screwed onto their cameras of the time fine. It's just today, 50 years later, people are trying to fit them to things that they weren't designed to fit.

Because the spacecraft and fighters were built in the same factories as Zorki and Fed cameras? 😕

 

[lynnb]

Thanks for the responses.

For the record, it screws in fine with my Fed3a and almost all my adapters.

It's just the 1 adapter and the Canon IVsb which has this issue. I'll try what you suggested Lyn. Trust Mainline to give us a low tech but effective solution!

Use a tiny bit of lithium grease to aid the process! I bought a small tube at a bicycle shop in King St Newtown.

 

[Dez]

As I understand it, the Leica screwmount uses an old English standard thread pitch of 26 threads per inch. Strange for a German product but that was an old standard used for microscopes, and Leitz was originally a microscope company. This is quite close to the standard metric 1mm pitch, although I believe the thread angle is 55 degrees rather than the metric thread's 60 degrees.
The Japanese and Soviet cameras used a 1mm pitch at least originally, and the Japanese mounts were typically more precisely machined, but of course precision is what you really don't want when having the wrong thread fit well enough to seat the lens. While the Soviets were obviously capable of producing extremely high quality equipment as listed above in this thread, I think it is fair to assume that different quality standards are applied to jet fighters and consumer cameras. So it's not too surprising to find a fair amount of variation in the lens mounts.

Canon changed their thread standard from something Peter Dechert called a "semi-universal" mount to (I think) the exact Leica 26TPI standard in the 50's, so except for really early Canons, FSU lenses that bind on a Canon will bind on a Leica as well.

Cheers,
Dez

 

[Dwig]

As I understand it, the Leica screwmount uses an old English standard thread pitch of 26 threads per inch. Strange for a German product but that was an old standard used for microscopes, and Leitz was originally a microscope company. This is quite close to the standard metric 1mm pitch, although I believe the thread angle is 55 degrees rather than the metric thread's 60 degrees. ...

The thread profile is as significant as the pitch. Even if you setup your lathe for 26 TPI (~1.024mm pitch) the resulting threaded part will clash with a true British Microscope Thread if the cutting tool used is shaped for the metric standard profile.

There are difference in both angle and whether there are flat "lands" at the bottom and top of the threads. There were a number of early M42 Pratika lenses that wouldn't mount on Asahi Pentax bodies because the top of the lens' male thread exteded to a sharp point and the Asahi body was expecting these to have small flat surfaces at the top. Grinding/sanding/filing off the tops of the male threads on the lenses would resolve the clash. I suspect that some of the FSU "LTM" fit issues are as much, or more, the profiles rather than the pitch.