A Question about shutters

[Dralowid]

On a Leica I (10xxx).

Z (or B) has become 1/20th. If I remove the cover I can make Z work properly if I depress the shutter release firmly.

Put the thing back together and Z reverts to 1/20th...sometimes.

Take the shutter dial off and curiously it is fine.

So what am I missing?

All else, (which on a I is precious little) is fine, OK so I have little use for Z(B) but it would be nice if it worked consistently!

Michael

 

[Mr_Flibble]

Added weight of the shutter dial might give the shaft enough momentum so the cam slips past the catch and releases the second curtain. Worn out part perhaps?

Does it do the same thing without the cover, but with the dial in place?

 

[Vickko]

yep, Mr Fibbles is right. The older Leica's are a study in body/metal distortion and relaxation. Even if you got it working, and you sat it overnight on the shelf, it might not work the next day, because the metal has relaxed and that tiny tiny amount of distortion that made it work, has relaxed and it won't work again.

But, if you are adjusting one with the top off, always have the shutter speed dial mounted. It is part of the mass/inertia of the system.

And, there is probably a tiny amount of grease or gunk that is preventing it from work. Find it, clean it out, relube it properly and it should work.

 

[Dralowid]

Yes, it only fails with the shutter dial on. Mr Fibble's comment re the cam missing the catch is 'on the money'. Having thought about what you both have said I realise that there is quite a lot of play in the 'main' shaft. Can't measure it accurately but I guess it is a 'fat' millimetre.

So, if that is what is causing the problem (and I imagine it is) I think I'll leave it alone. It's 85 years old so I guess allowances can be made!

 

[john neal]

Michael,

There is probably a mismatch between spring pressures here - the big flat one on the base is probably in need of adjustment, so that it doesn't overwhelm the small one under the bell housing at the top. It is a real fiddle, and one that I don't enjoy at all.

You haven't loosened any screws in that area have you?

 

[Penny Lane]

What John says!

However, when I built up a Zorki-1 from spares, I found that the catch shaft was just a tiny bit too long, so that the catch would never end up flat against the top plate. I can imagine how, in rare cases, this might happen if an elderly Leica has had a part replaced at some point. The spring balance theory being the answer is much more likely though.

Derk

 

[Dralowid]

Michael,

There is probably a mismatch between spring pressures here - the big flat one on the base is probably in need of adjustment, so that it doesn't overwhelm the small one under the bell housing at the top. It is a real fiddle, and one that I don't enjoy at all.

You haven't loosened any screws in that area have you?

Hi John, no not fiddled with either. If I understand you correctly, if the big flat spring on the bottom of the crate is too 'strong' then the little hair spring on the top won't be man enough to press the (Z/B)catch down???

Will ponder awhile.

Michael

 

[Dez]

I agree with John. The balance between these two springs is critical and getting it right can be fiddly. A buildup of crud on the vertical shaft or anything binding the upper spring could be a problem as well. It's best to take the shaft with the shutter latch out and clean everything before making any changes in the springs. The bottom spring is moved directly by the action of the shutter button, so its tension rarely needs looking after, but the upper spring does sometimes get tired. Another thing to look for is the synchronization of the release of the upper latch with the release of the dogs coaxial with the take-up spool: the latter has to happen first.

Cheers,
Dez

 

[john neal]

Michael,

Yes - as Dez says, the top spring is most likely tired and not providing sufficient down force. It is not easy to adjust the small one, especially if the steel has lost it's spring.

However, do check and make sure that the rewind lever has returned fully to the "wind" position - had one on an IIIc that foxed me for weeks because it would fire accurately at all speeds except 1/1000 and Z. The rewind cam was not returning all the way, although the lever looked as though it was.

In a Fed this problem tends to manifest itself as a one speed shutter (1/50), regardless of what you have set (I have one like that).

Not sure, but DAG may have some original springs (or CRR, maybe)

 

[Erik van Straten]

Not sure, but DAG may have some original springs (or CRR, maybe)

It is possible to make the spring yourself from the right size piano-wire.

Erik.

 

[Dralowid]

I've been at the camera again this pm and I'm back where I started. All is clean. The shutter is 100% with the dial removed and then the moment I replace the dial, B is lost. The little top spring has 'spring' in it and seems to be doing its job.

I am inclined to go back and accept what Mr Fibble says, there is so much play in the main 'shaft' that the additional weight of the dial makes the second blind miss the catch. To prove this I can make B work with the dial fitted by pressing the shaft to one side (towards the back of the camera) so that the play is taken up.

I've got plenty of old Fed Is that I could cannibalise for a shaft etc but not sure if it would fit, also it seems a shame and I may yet give myself the project of bringing some of them back to life sometime.

 

[john neal]

It is possible to make the spring yourself from the right size piano-wire.

Erik.

Erik,

That's true - I use a piece of plywood with pieces of piano wire set in the right position to form the loops - something of a hangover from model aircraft technology.

Michael,

I wonder if you could either build up the shaft (chroming?) or somehow bush the hole if the shaft is really that sloppy in the frame? Alternatively, a stronger top spring might just push the shaft to where it should be.

I don't think the Fed parts will fit - they are much simpler than the Leitz ones (not to mention somewhat more "agricultural" in quality and finish).

 

[Dralowid]

John,

My experiments with the spring have shown that making it apply more pressure doesn't do the trick but nevertheless I may take Erik's advice and have a go at making one, there is the remains of an auto harp in the garage somewhere.

However, first I'm going to compare the sideways play in this shaft with some of my other cameras and ponder awhile. Shame I haven't got any other Is left, they are so easy to pull apart!

best

Michael

 

[john neal]

Well, it should exert pressure in two directions - down and forward (IIRC) would that just make it worse? If you are thinking of making a spring, don't try to put any loops or bends too near the end of a piece of piano wire (but you probably already knew that).

Maybe the brass of the chassis has worn over time - the rod will be much harder than the brass. I guess Malcolm T or Peter could fix it for you, but there would be a price attached.

 

[Dralowid]

I think I'll leave it as it is and avoid spending £££s.

It's quite fun, I've used it again this year but realise I really do miss a rangefinder...or focus peaking...

 

[john neal]

...or focus peaking...

Oh dear, it sounds like you are going the same way as me - I now have a Fuji XE-1 as well as the Nex and I love it (dare I say better than M8 performance at a fraction of the price?) :angel:

Some Leitz products to sell this weekend, methinks...

 

[Erik van Straten]

first I'm going to compare the sideways play in this shaft

Did you try to install a well fitting washer at the end? Some have one and others don't.
Washers in Leicas are usually very important.

Erik.

 

[Dralowid]

Erik, thanks, hadn't thought of that.

No washers present. I'll check the 'end float' of the shaft and see if there is much but I think not.

(assuming end float is the correct terminology?)

 

[Dralowid]

Oh dear, it sounds like you are going the same way as me - I now have a Fuji XE-1 as well as the Nex and I love it (dare I say better than M8 performance at a fraction of the price?) :angel:

Some Leitz products to sell this weekend, methinks...

John, off topic I admit but yes, after some Leica gear sales I too have a Nex 6. Love the viewfinder. I'm like a college student who has just discovered a supply of free film! Using ltm, m and r lenses (with your adapter). Favourite results so far from 2.8 Summaron and 135 Tele Elmar. Looking forward to seeing what Summar and Summarit will do.

A rejuvenating experience!