Old Rollex spacings (again)

[Barry Kirsten]

I've read the 2003 thread about spacing overlap in old Rollex backs, and the consensus there was that the problem is due to thinner film base and backing paper these days compared with earlier films.

I have just put a roll of film through a newly acquired Linhof 6x9 which has an older knob-wind Rollex back, and found the expected frame overlap - more at first, less toward the end of the film. There can be no possibility of wear in this case as the back (and camera) have had very little use. The problem is no doubt due to today's thinner films.

I have seen a different thread on this forum in which there was discussion about adjustment being possible to these backs. Of course, now that I want to follow up the thread, I can't find it - Murphy's [or someone's] Law!

I'm keen to fix the problem once and for all, as I'm not sure that giving an extra 'tweek' to the knob at each frame is a workable solution. Does anyone know of any adjustment that is possible for these backs?

Many thanks,

Baz.

(BTW film turned out great - Efke and PMK, beautiful!)

[cps]

Baz,

I am in exactly the same boat. Here is the thread I think you are talking about. The last poster suggests that an adjustment is possible, though he had no recollection what it was that he did.

http://www.largeformatphotography.info/forum/showthread.php?t=67221

Chris

[Barry Kirsten]

Yes, that's the one. Thanks, Chris.

I don't accept - at this stage, without having taken it apart - that we have to put up with a compromise solution. I'll have a look at it and if lucky enough to be able to fix it, will post the 'recipe'.

Baz.

[oibal60]

Hi,
Have the 'knob' Rollex back myself.
I did a search (web) and one person 'increased the diameter' of the take-up spool by wrapping it with masking tape -- which seemed to 'fool' the mechanicals enough to prevent 'overlap'.
Am about to run a couple of rolls (of 120 B+W) thru my own 6x9 Linhof ST IV. This will be the first time the camera will have been out of its box and 'used' in... (get this) 26 years!
I plan on running the first roll - as is - and seeing the results. Then I'll 'judiciously increase the diameter', take some more pix, and see what the story is.
We gotta get to the bottom of this dilemma !
Gerry

[Jim Noel]

Another test would be to run a roll of Foma or Arista Edu through he camera. They are thicker films on a thicker paper base.

[Barry Kirsten]

Hi,
We gotta get to the bottom of this dilemma !
Gerry

I agree, Gerry!

I'm currently running tests using a roll of film to see what I can learn about the problem. I have to re-roll and tape the film each time, and make marks on the backing paper through the window slot in the film holder insert. I haven't had any blinding revelations yet, but hope that may reveal something.

I have also had a look at the mechanism, by partly removing the cover plate. I'm amazed at its precision and beauty. At this stage I'm not prepared to do anything drastic until I can see a solution. 'Fools rush in...' and all that.

What I would really love is a good set of drawings of the mechanism. These would have to be around somewhere. Anyone have any clues?

At the moment all options are on the table - like adding tape to the take-up spool, or giving an extra tweek to the knob at every frame (possibly an extra 90 degrees?) - but I feel that the best solution would be to make an adjustment to the mechanism to effectively increase the length of each stroke; that's why I would like a set of drawings, to get a better appreciation of how it works.

We'll keep tryin'.

Baz.