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Topic: Aligning 70MM trap rollers
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Steve Guttag
We forgot the crackers Gromit!!!
Posts: 12814
From: Annapolis, MD
Registered: Dec 1999
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posted 11-18-2009 04:54 PM
Ah...the Simplex 35/70...
In truth, the lateral guide rollers on the Simplex 35/70 are a little dubious. The problem stems from the fact that the film path is set up for 65mm in every other place BUT the lateral guide rollers and the pad rollers. As such you don't get a clean reference and in the case of the lateral guide rollers, they will actually curl the film around the runners.
If the film is not stiff in the area of the lateral guide rollers, then their absolute lateral position can't be achieved since you have figure out the amount of curl in the film as the film will hit the roller at an angle. I've been known to cut a coil or two off the spring on the LGR to allow the film to not curl.
In general, I've found it best to first mechanically center the film on the intermittent sprocket and then, by feel, tweak the roller position a little to see if it improves lateral stability...on the Simplex 35/70...I haven't seen much difference, if at all...in fact, I've once tried just taking them out! It only seemed to make threading harder.
Lord only knows why the sprockets, gate/trap...etc were not expanded to be true 70mm devices rather than living with a legacy that NOBODY needed for at least 30-years!
Steve
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