Jupiter 8 Seating onto Leica 111 Problem

[wolves3012]

Ural Mars indeed, probably blue and with sidecar. I think I remember that one infuriating problem with these was that the mixture screws were underneath the carbs screwing upwards and, as a result, had a habit of dropping out.

My BMW has mixture-adjustment screws that screw in from underneath, screwing upwards. However, they don't fall out, so it's the implementation that's flawed if they do, not the concept.

Regarding FSU lenses on Leica, I have some Industars that aren't very happy to mount on my IIIC but all the J-8s I've tried are fine. Leica's threads are, undoubtedly, machined to tighter tolerances and that may well be the explanation for the OP's problems.

 

[David Hughes]

No politics anywhere in my post David and also I'm nowhere close to Russia, geographically nor ideologically.

Is there anything regarding engineering (the only scope of my post) that I wrote and you disagree with? I'm always keen to encounter new views

Hi,

Ooops, I was commenting on the thread in general when I mentioned politics. Sorry if it looked as though I was aiming at you. and your post which I agreed with.

Regards, David

 

[David Hughes]

The earlier posts are correct about the Soviet thread standards. I trust they know the history better than I. The problem is production. I'm a retired machinist and know that threads need to be made with great care. They are also challenging to measure in a production setting. Usually a thread gauge is used to check the results. The gauges can wear as they need to be used often. The machinery making the threads needs to be high quality, in good shape and reliable. This is not just a Soviet problem. I recently bought a new adapter for Pentax screw lenses to my LTM cameras. It would not screw fully and easily into my IIIc's but would fit my Zorki's and my 1934 Leica II. I mean no disrespect to earlier posters and I'm grateful for them sharing their knowledge. Joe

Hi,

I often wonder how many people commenting of the Leica/FED/Zorki combinations know what a thread gauge is, and how many own one...

Perhaps a poll is needed.

Regards, David

 

[David Hughes]

Ural Mars indeed, probably blue and with sidecar. I think I remember that one infuriating problem with these was that the mixture screws were underneath the carbs screwing upwards and, as a result, had a habit of dropping out.

Hi,

There's a version of LocTite (it's blue from memory) that solves this problem. It's used in the gun trade on trigger adjustment screws to make them vibration proof. It will also take up a bit of play in the threads.

Regards, David

 

[johannielscom]

Hi,

Ooops, I was commenting on the thread in general when I mentioned politics. Sorry if it looked as though I was aiming at you. and your post which I agreed with.

Regards, David

Ah, that sorts it out then! I was a bit confused and thought I had actually encountered an unknown language barrier somewhere😀

Happy shooting!

 

[Roger Hicks]

Hi,

I often wonder how many people commenting of the Leica/FED/Zorki combinations know what a thread gauge is, and how many own one...

Perhaps a poll is needed.

Regards, David

Dear David,

And indeed, if they own thread gauges (as I do) are entirely competent at using them (as I am not).

Cheers,

R.

 

[Livesteamer]

If you want to see some really fine threads, pick up a Leica ASPH lens or a Noctilux. The focusing helicoid is essentially a high quality thread with as little play as possible. And if you ever get a chance, watch a modern CNC lathe put threads on a part. Bless my threading dial, it's lovely. Joe

 

[Dez]

There are four turns in a typical LTM mount. The 26 TPI thread translates to a 0.977mm pitch, so the total difference over the thickness of the lensmount is 0.09mm or .0036" between a lens designed for 26TPI vs one designed for 1mm pitch. This is the same order of magnitude as the tolerance one could expect in a decently-cut thread. If the FSU lenses and bodies have as much variation as they are reputed to have, I would expect some to be just fine and some bind. This would be the case for FSU lenses on a Leica body and vice versa. The problem would still exist to a lesser extent for an FSU lens on an FSU body as well, and I have seen that happen.
Does anyone know for sure if Canon used the 26TPI standard or the 1mm one? Or Nikon in their LTM lenses?

I doubt if the sharpest eye could detect that difference with a thread gauge with only four turns. As for the 50 degree vs 60 degree thread angle, I probably would have a hard time but maybe someone with keener eyesight would see it.

Cheers,
Dez

 

[Dralowid]

Michael,

Wasn't there a risk of getting your leg trapped by the bars that held the chariot on too?

Mixture screw? Just use a sharpened twig !!

John you remember the bad bits!

Yes, it really turned out to be the wrong thing for cruising the King's Road in those far off days, danger of ripping one's flesh coloured hipster loons!

(Now that IS remembering a bad bit!

 

[David Hughes]

Ah, that sorts it out then! I was a bit confused and thought I had actually encountered an unknown language barrier somewhere😀

Happy shooting!

Hi (again),

I knew several people who were seriously into optics and they were very flattering about Russian optics. In a nutshell they thought them excellent but a little old fashioned. I remember one saying that the only thing he could suggest to improve something was bolting the tripod to a concrete floor...

One was curious about them and even took each element out and measured and checked it very carefully and was still saying nice things about it.

I think the biggest problem is that we are talking about second-hand cameras here and a lot of people sell on duff ones, instead of repairing them. Sometimes I wonder if there's only half a dozen duff ones that have been sold on over and over again.

As for politics, I often think this forum should be called "FED and Zorki RF" as every other camera make has a forum with the maker's name as the title. Alternatively we could use "loaded" titles for each forum. OK we don't see "commie" so much in these threads these days but I've yet to see "Nazi" elsewhere.

BTW, I'm just asking for a level playing field, nothing else.

OK, rant over; I'll go and lie down after taking a tablet. ;-)

Regards, David

 

[David Hughes]

There are four turns in a typical LTM mount. The 26 TPI thread translates to a 0.977mm pitch, so the total difference over the thickness of the lensmount is 0.09mm or .0036" between a lens designed for 26TPI vs one designed for 1mm pitch. This is the same order of magnitude as the tolerance one could expect in a decently-cut thread. If the FSU lenses and bodies have as much variation as they are reputed to have, I would expect some to be just fine and some bind. This would be the case for FSU lenses on a Leica body and vice versa. The problem would still exist to a lesser extent for an FSU lens on an FSU body as well, and I have seen that happen.
Does anyone know for sure if Canon used the 26TPI standard or the 1mm one? Or Nikon in their LTM lenses?

I doubt if the sharpest eye could detect that difference with a thread gauge with only four turns. As for the 50 degree vs 60 degree thread angle, I probably would have a hard time but maybe someone with keener eyesight would see it.

Cheers,
Dez

Hi,

I was told that Canon used both, 1mm at first and then realised and created a hybrid.

Trouble is thread standards change. Look how many versions of (say) quarter inch Whitworth exist (or existed) to say nothing of the unknown ones car makers used on exhaust systems.

And I wonder how many people know what RMS stands for and its relevance to Leica etc?

Regards, David

 

[Dez]

Hi,

I was told that Canon used both, 1mm at first and then realised and created a hybrid.

Trouble is thread standards change. Look how many versions of (say) quarter inch Whitworth exist (or existed) to say nothing of the unknown ones car makers used on exhaust systems.

And I wonder how many people know what RMS stands for and its relevance to Leica etc?

Regards, David

I have for many years ridden elderly Triumphs, with their truly wondrous combination of BS, BSW and SAE screw threads. With enough wrenches and enough patience, I have generally had little problem with them, due in large part to the "automatic external lubrication system" enjoyed by most old Britbikes.🙄

OK, I'll bite. To me, RMS means root-mean-squared, as in AC mains voltage. I suspect you have a different version though.

Cheers,
Dez

 

[David Hughes]

I have for many years ridden elderly Triumphs, with their truly wondrous combination of BS, BSW and SAE screw threads. With enough wrenches and enough patience, I have generally had little problem with them, due in large part to the "automatic external lubrication system" enjoyed by most old Britbikes.🙄

OK, I'll bite. To me, RMS means root-mean-squared, as in AC mains voltage. I suspect you have a different version though.

Cheers,
Dez

Hi,

It's "Royal Microscopical Society" who decided to standardise things years and years ago. The point being that Leitz (and Zeiss for that matter) made microscopes and so would work to the RMS's standards. And I guess Barnack went to the stores for bits and pieces and so the early Leicas (or all of them?) were fitted with screws, screw threads etc to that standard.

Old British bikes plus modern sealants etc changes a lot, I was told when my Dad worked for a well known racing firm. Plus in the UK anyone on an old bike will be stopped and chatted to by the police who love them too. At one time you could bet anyone of a certain age on a bike was a copper off duty. It still works as a rough yardstick these days.

Regards, David

 

[Dez]

Thanks, David: that's very interesting. No doubt that is the reason for the original thread standard used by Leitz.

I wonder if the old Britbike appeal works for Canadian coppers. I do get lots of friendly comments on the days when I am riding rather than wrenching.



Cheers,
Dez

 

[Livesteamer]

Wow! A lovely Triumph Trident. And you keep it running!

You're Good.

Joe

 

[Baybers]

Very nice bike Dez. Bought a T140v Bonnie in 1973 and loved it despite going through gallons of oil and speding every 3rd weekend tightning numerous screws and bolts...

Meantime, I have posted my original question on the Classic Motorcycle forum....

 

[David Hughes]

Thanks, David: that's very interesting. No doubt that is the reason for the original thread standard used by Leitz.

I wonder if the old Britbike appeal works for Canadian coppers. I do get lots of friendly comments on the days when I am riding rather than wrenching.



Cheers,
Dez

All part of the service ;-)

I guess old bikes and old cameras break down barriers. I get a lot of people chatting when I use either, but my idea of an old bike is a Moulton...

Regards, David

 

[Baybers]

A follow up. The older chap I referred to in an earlier post has re-machined the thread pitch to 60 degrees instead of the 55 that the lens had. Result is the lens now screws on with no problem. Cost AUS$55.00.
If you are in Australia and require some servicing of your vintage camera then I can think of no-one better than Alan at www.f16cameraservice.com.au