This is topic FEED PINS on AW3 Feed Cluster/Brain/Centerpiece - whatever you wanna call it. in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Scott D. Neff (Member # 185) on 05-17-2000, 12:42 PM:
We have some older model AW3's with the NARROW pins that guide the film into the 3-Rollers on the brain. Our ex-tech insisted that these NARROWER pins were causing scratches because they are more likely to touch the image area of the frame.Has anybody else found this to be the case? I BELIEVE that I get scratches from something in the auditoriums with those platters (more than the ones with the newer AW3s) Just trying to figure out what it MIGHT be.
Posted by Brad Miller (Member # 2) on 05-17-2000, 02:42 PM:
Your tech is correct. Anyone using those older pins should replace them with the newer style as they can cause a scratch right down the center of the base side of the film (projected slightly off center left).
Posted by Scott D. Neff (Member # 185) on 05-17-2000, 07:56 PM:
I have the larger pins on hand... but the plate and the screw-block are drilled too close together for the new pins to fit. I can't convince the owner to purchase new ones. Is there anything I can do to make THESE better?
Posted by Jon Bartow (Member # 241) on 05-17-2000, 09:07 PM:
Being very patient you can file or sand the pins into a similar shape as the larger type. Of course the groove will not be as deep as this will weaken the pin too much. You should strive for a shape that will touch as little of the film as possible. Be very, very sure that there are no burrs whatsoever on the pins before they come close to film.
Posted by Brad Miller (Member # 2) on 05-18-2000, 02:08 AM:
Do you have the small plate that the pins bolt onto from underneath? If so, you can drill out the dust cover's holes to match.
Posted by John Pytlak (Member # 331) on 05-18-2000, 07:41 AM:
Jon:I wouldn't have your patience. It is very difficult to hand sand the pins into the correct "undercut" shape, without significantly weakening them or risking a rough spot that could abrade the film.
It is also important to maintain the proper relative humidity in the projection room (Kodak recommends 50 to 60 percent RH). I know of one case where an entire 70mm print was base-scratched on the platter guide pins because the humidity had gotten so low (around 20 percent RH) that the film shrunk and cupped enough to have the center contact a rough spot on the pin. An accurate digital humidity gauge from Radio Shack or Edmund Scientific is a good investment.
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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com