8mm Forum: Chinon dual 8 is eating my film

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Posted by Chris Drumma (Member # 380) on May 08, 2005, 11:27 AM:

I have a dual 8 with a rabid appetite for 8mm film. For some reason it keeps getting wrapped around the 1st sprocket and tears the film eventually. It also is making a clicking sound from the film hitting the thread lever(green push lever on top) when I can get it to thread. I have heard the dual 8's are hard on film. Kinda hard to explain without pictures but can anyone help?
thanks
Chris

Posted by Jan Bister (Member # 332) on May 08, 2005, 04:04 PM:

Does this happen only with 8mm film (not super-8)?
Is the sprocket maybe greasy or sticky? Does film run through the machine OK once you got it threaded all the way? Any problems during reverse projection?

Posted by Tim Christian (Member # 48) on May 08, 2005, 04:33 PM:

Which model Chinon? Some use a clever dual-gauge sprocket (also used by Yelco) whose teeth are both coned and tapered so that both R8 and S8 film sit at the right diameter and the proper distance across the film path. If the these sprockets have any dirt build up, they don't work properly and film may be damaged.

Posted by Jan Bister (Member # 332) on May 08, 2005, 06:36 PM:

Good catch there Tim. Didn't know some Chinon dual machines used this kind of sprocket. I have one exactly like it on my Elmo 912 dual-8 editor and it's quite an ingenious design. But if one of the teeth should be chipped or bent or otherwise damaged... it's easy to see how 8mm film (with its larger sprocket holes) could get caught and eaten up.

Posted by Chris Drumma (Member # 380) on May 09, 2005, 11:41 AM:

It is a model 727. I have not tried it yet with super 8 film. I only have a couple super 8 films I would be willing to try it on. It does run throught the machine if I can get it that far but it has an annoying clicking sound of the film hiting the green lever while it is being projected.
thanks,
chris

Posted by Rick Skowronek (Member # 385) on May 09, 2005, 07:04 PM:

Thought I came across one of the gurus stating that this type of problem was due to a misaligned upper sprocket with regard to the film gate. Don't know but I think it was Kevin who said to loosen the upper sprocket and realign. Just a thought.

Rick

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