Film-Tech Forum ARCHIVE: Sproket Hole Riding Prints

This is topic Sproket Hole Riding Prints in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Chad M Calpito (Member # 3736) on 05-25-2006, 01:45 AM:

I have a question. Recently, I've seen a few prints that have been sproket hole riding and it concerns me. Now, I am sure that it can happen because of poor threading. Before I ask my question, I always double check my threading, sometimes, even triple checking my threading. Also, I am currently using the Simplex 35 Projectors in my booth, except for #4, which is an old style Century Projector that is a 35/70MM. Anyway, here is my question. What are some other causes that can make a print be Sproket Hole Riding? What I have seen and felt is the non-soundtrack side of the print. I am open to suggestions as to how I can rectify the situation. Of course, proper film threading from the platter, through the projector & sound heads and back to the platter is important. Any ideas and suggestions would be greatly appreciated. Thanks. [Big Grin]

Posted by Monte L Fullmer (Member # 2797) on 05-25-2006, 02:17 AM:

Are you a discount house where you are getting used prints..or a first run house?

Many causes...

1- Sprocket run can be caused by bad splices - splices that the holes are completely punched out, thick splices (splices that are made over old splicing tape..why you should clean off the old tape before making a new splice..)

2 - misaligned pad rollers -rollers that are too tight against the sprocket itself,thus pinching the film inbetween and causing the film to ride on the teeth.

a- where you have Simplex 35, and presumably with 5 star soundheads..the lower pad roller assembly on that soundhead is held on by a shaft that has a big flat blade screw head that LOVES to work itself loose, causing the two pad rollers on that assembly to be misaligned with that sprocket - and sprocket running that print.

3- with that Century "JJ" 35/70 machine, the sprockets are travelling a lot faster in rotation than the Simplex 35..but the same..watch out for your splices and the pad roller/shoe alignments..

some areas to look at in the future..

-Monte

Posted by Chad M Calpito (Member # 3736) on 05-25-2006, 09:59 AM:

We are a first run movie house. We also have the 5 star soundheads for all theatres. I should have mentioned that in my original post. My bad. Anyway, thank you so much for the information, Monte. [Big Grin]

I know that a part was replaced on the Century "JJ" 35/70 projector, just below the intermittent sprocket.