Film-Tech Forum ARCHIVE: Century SAW adjustment of trap

This is topic Century SAW adjustment of trap in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Kenneth Wuepper (Member # 1174) on 11-25-2002, 06:46 AM:

In the Westar version of the Century SA projector head:

Where is the distance between the aperture plate and the movable film gate adjusted. I do not see the usual stop screw as found in the Simplex XL or similar machines.

This adjustment should set the relationship between the gate rails and the aperture plate. It also will impact the tension range of the bands.

Thanks, KEN [Confused]

Posted by Pete Naples (Member # 761) on 11-25-2002, 12:35 PM:

Assuming your Westars are the same as ours ?

There are two adjustments. One adjusts the 'cleaning' position (the gate is neither fully open or fully closed) by loosening two small allen screws above and below the collar of the gate opening knob, with teh knob in the middle position you rotate the entire knob assembly until happy, then tighten the screws.

To adjust the fully closed postion you move the entire lens holder assembly to and fro, after slackening it's mounting screws. This requires the removal of the lens, and moving the focus control about until you can access the heads of the screws.

Hope this helps.

Posted by Mark Gulbrandsen (Member # 72) on 11-25-2002, 06:20 PM:

The normal clearance is about .25" to .3" measured between the flat plate the curved runner is mounted to and the operator side fixed lateral film rail. I would assume the Westrex version is the same.
Mark @ CLACO

Posted by Kenneth Wuepper (Member # 1174) on 11-25-2002, 09:24 PM:

Pete and Mark,
Thank you for the insight into these adjustments and their tolerances.

This machine was dismantled and re-assembled by someone else and it is leaving deposits of hard material on both the bands and the curved runners in the gate area.

Do you have any suggestions for curing the deposit problem?

Thanks again, KEN

Posted by Mark Gulbrandsen (Member # 72) on 11-25-2002, 10:06 PM:

Ken,
Be sure there are no rough spots on the curved runner and also be sure that the bands are not rough. New bands are cheap, less than 10 bucks. Too much gate tension may also cause this buildup as well. If this is occurring on new film then it may just be edge wax deposits so checking and cleaning the runner and bands between shows is important to prevent the buildup. You can also use Filmguard....it is amazing at preventing crud from building up in the trap.
Mark @ CLACO

Posted by John Pytlak (Member # 331) on 11-26-2002, 08:14 AM:

Buildup of hardened gelatin on the bands is more likely with freshly-processed "green" prints. Use the lowest gate tension that still gives a steady image. After a few passes, the emulsion will be more "hardened" and less likely to abrade and build up. Since high humidity also can make the gelatin emulsion softer, be sure to keep your RH in the recommended range of 50 to 60 percent RH. Proper lubrication of the print (SMPTE RP 151), or applying a hard wax like carnauba wax to the bands also helps.

Using anything metal to remove the hardened deposits from the gate or bands is likely to cause a rough spot or burr that will just cause more abrasion and buildup. Use a fingernail, wooden/plastic cuticle stick, plastic guitar pick, or just a good stiff bristle tooth brush to remove the deposits.

Posted by Kenneth Wuepper (Member # 1174) on 11-29-2002, 06:23 AM:

Thanks to all of the posters for your positive and helpful input.

This information is what the FORUM is designed to deliver.

Sincerely, KEN