zorki 6 film advance problem

[reagan]

File 0.1 to 0.2 mm off the back of the flange.

Yep, that would do it. However, I'm not sure my hand file skills could bring the lens mount to a flat parallel with the film plane. What are the tolerances again? + - .02mm, right?

How about stripping the paint (if any) off the face of the mount on the body?

Yeah, I would think a good cleaning right down to the metal and maybe a little metal polishing there and the back of the lens mount would help. Also making sure that any glue, etc. from the edge of the cover or the cover itself isn't bleeding into that area. I don't think it would take much "debris/paint specs/50yr.old stuff" here to make a 0.1 or 0.2mm difference.

There's also a backside cutaway of approx. 1.24mm depth in the top of the lens mount (see photo) that allows it to hang over the edge of the RF/VF housing. Machining off the back side will make this cutaway more shallow. There seems to be some room to work with on my Zorki.5 and Zorki.1s c & d, but the Zorki.1b is a pretty tight fit in this area. One might be wise to double-check clearance there before metal is removed.

note: Whilst looking over said cutaway, (from my Zorki.1b) I ran my fingernail around the cut edges and found a bur raised approx. .05mm just above the red arrow in the photo. No doubt it was left over from the cutting tool. hmmm.

 

[Xmas]

Glass plate and rough valve gringing paste, hold it down with large flat surface, check that it is really flat first, i.e. that the stand off from the pressure plate is uniform, you may be able to improve on the current fit as well as remove metal.

You also need to measure with a thick film in place & between the rails as the depth is to the near rail not to the plate...

You need luck

Noel

 

[Nickfed]

Yep, that would do it. However, I'm not sure my hand file skills could bring the lens mount to a flat parallel with the film plane. What are the tolerances again? + - .02mm, right?
Yeah, I would think a good cleaning right down to the metal and maybe a little metal polishing there and the back of the lens mount would help. Also making sure that any glue, etc. from the edge of the cover or the cover itself isn't bleeding into that area. I don't think it would take much "debris/paint specs/50yr.old stuff" here to make a 0.1 or 0.2mm difference.

Pardon my scepticism but.......

I think the first thing to do is to have a look at 0.02mm and see just how big it is. You may then conclude that your hand file skill are indeed not too appropriate. Perhaps a quick lick over 600 wet and dry may be better...

The second thing to do is to check whether +/- 0.02mm is indeed the spec. I'm not sure of this but if you find it is +/- 0.2mm, remember where you heard it first.

The third thing to do is sit down and consider whether you really need to do this. Some basic physics might help. Read before you file.

 

[reagan]

Tolerance-wise, I searched RFF threads and found this attachment, a pdf. of Leica.IIIf service manual, which reveals the tolerance to be +0.015mm to -0.005mm. Geez.Louise! As I stated, I personally didn't have much confidence in my being able to hand file to +/-0.02mm tolerances. Holding the actual tolerances are out of my league for sure.

The valve grinding grease that Noel mentions is more what I had in mind when I suggested "polishing" cleaning ... the use of some sort of lapping compound applied with a known [very] flat surface.

"...consider whether you really need to do this... before you file."

I agree for sure. So far, after shooting the a first few rolls through each of my Zorkis n' Leicas, since I'm not a "gotta-have-tack-sharp" sort of photog, I've yet to even go looking for shims. But in the event, one day down the road, should I decide to tweek the beaters to tighter specs, info from these discussions should prove quite valuable. Thanks for all the input guys! (...even though we have successfully carried this waaaaay OT! )