Film-Tech Forum ARCHIVE: Christie horizontal weave

This is topic Christie horizontal weave in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Phil Ranucci (Member # 3820) on 04-22-2012, 12:33 AM:

I've got a few old GPC Christies with the shutter gear box and the reversing gears on the intermittent. One machine has a really bad horizontal weave. I reset the lateral guides with the Christie tool (twice) and no improvement. I then swapped a gate from a steady machine and with the gate from the steady machine it was still unsteady. What else besides lateral guide rollers causes weave? Any ideas?

Posted by Monte L Fullmer (Member # 2797) on 04-24-2012, 09:07 PM:

Can you see the weave in the aperture opening? How's the tooth belt running the assembly - new or tired? Is this the one where the plastic gear is driving the intermittent assembly, and if so, is there paper thickness between the two gears?

Posted by Brad Miller (Member # 2) on 04-27-2012, 07:13 PM:

Constant smooth weave or random violent side to side movement?

Posted by Randy Stankey (Member # 64) on 04-27-2012, 09:02 PM:

If the intermittent sprocket isn't perfectly aligned with the film trap it can cause weave.

The film isn't being pulled straight down through the trap, causing it to "pinball" off the guides and/or the guide wheels.

Check to see that the trap is inserted and fastened properly and that the sprocket is correctly aligned.

An improperly aligned intermittent pad shoe can also cause horizontal weave and/or vertical jitter. (Jitter being the most likely.)

Sometimes, you need an alignment tool to make the adjustment. Other times you can use a steel straight edge. If neither of those are available, you can take a piece of film, trap it in the gate and use that to align the sprocket.

Using film to align the sprocket should be considered the least accurate. A straight edge is second best. If you can get an alignment tool for your projector, that would be the best.

If I remember correctly, Christie does (or did) make one for their projectors. This device, if it can be had, would most likely be the property of your theater's technician.

It's probably best to call your tech, anyway.

Posted by Louis Bornwasser (Member # 3063) on 04-29-2012, 05:37 PM:

If the small ruby lat guide roller bearings are missing, you would get weave. Louis

Posted by Phil Ranucci (Member # 3820) on 04-29-2012, 07:11 PM:

It's a smooth weave. The belts are about 2 years old.Gears are set to quietest point. I'm pretty sure the rubies are present, when I'm there next I'll check, and also check the intermittent sprocket.
Thanks!