This is topic Pad Rollers Suppose to move or not? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.


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Posted by Jason Setzer (Member # 3949) on 10-21-2006, 05:08 PM:
 
Ok this is a 2 part question.

It has always been my knowledge that the upper pad roller is suppose to move during operation and the lower pad isn't.

Also we have old C Century projectors that have the rollers with the "inner shoulders". Are these ok to have or should we get these replaced?

I was one of our other venues this week and when I came back 2 of our prints having scratches. One was very light black vertical scratches towards the left center of the screen which I believe to occured from the tension being to lose on the lower pad ( which was making the loop have more movement than normal causing the film to get scratched) but wonder what the other scenarios could be? The other one was 7-8 vertical scratches I think was caused simply by a misthread.

Apologize in advance for making this a double sided question

[ 10-22-2006, 06:13 AM: Message edited by: Jason Setzer ]
 

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Posted by Frank Dubrois (Member # 3042) on 10-21-2006, 05:13 PM:
 
I always thought rollers were named that because they were supposed to roll. Its been my personal experience all rollers are supposed to roll, otherwise you'd just be dragging film over a rounded piece of plastic.
 

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Posted by Ken McFall (Member # 845) on 10-21-2006, 05:53 PM:
 
Depending on the projector I would be more concerned if the rollers were turning all the time as that would suggest they are riding on the film which is not how they should be set!

Rollers should be set two film thicknesses off the sprocket. I set them up with a long loop of film running and a finger resting lightly on the roller assembly. As the join goes thru you should not feel the join 'kick and lift' the roller very hard. I adjust the rollers so I can just, and no more, feel the splice go thru.

Film that has been laced correctly on the sprockets and with correctly set pad rollers cannot cause scratches in the sound track or picture area of the film as they are recessed.....

You should also remember that the film is effectivly stationery as it passes over sprockets so there is no mechanical wear caused by sprockets on the film surface. Hooked spockets of course are a different matter, but again would not cause scratches.
 

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Posted by Aaron Mehocic (Member # 15) on 10-21-2006, 06:05 PM:
 
Pad rollers should be maintenanced at least once per year. The old brass rollers in early model Simplex machines have an actual hole inwhich lube can be applied directly onto the shaft so they can spin. The plastic rollers don't. They must be removed at the gate. Some guys I know use everything from projector oil to a synthetic compound made by Dupont Chemical to lubricate the rollers. I mostly just take the roller off, clean the shaft and use a dab of 3-in-1 (sparingly).
 

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Posted by Tim Reed (Member # 137) on 10-21-2006, 06:19 PM:
 
If you have nylon rollers, they are supposed to run absolutely dry, with no lubrication whatsoever. Even a light film of oil will cause them to stop rotating. This often causes much confusion, because a person will take apart the whole shooting match, thoroughly clean the shaft and inside of the roller, lube it, put it back together, and it's stopped rolling again by the end of the week.
 

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Posted by Aaron Mehocic (Member # 15) on 10-21-2006, 06:42 PM:
 
Tim is right about the nylon (plastic). I didn't clarify that above. We have many styles of pad rollers here.
 

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Posted by Bernard Tonks (Member # 809) on 10-21-2006, 07:03 PM:
 
I had a nylon roller at the top of my Westar 2001 projector heads. No oil, and thoroughly clean the shaft and inside of the roller as Tim says. If you also coat the shaft with a soft lead pencil, will keep the roller turning really freely. Same applies if you have a metal roller in light loop film contact between projector and soundhead.
 

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Posted by Richard May (Member # 2627) on 10-22-2006, 07:26 AM:
 
I have replaced all the rollers that have that inner ridge on them. I have found them to scratch the film when they stop spinning. The newer rollers dont have that inner ridge.
 

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Posted by Mark Gulbrandsen (Member # 72) on 10-22-2006, 08:23 AM:
 
I prefer the best rollers available for the most part. The MNR422 from LaVezzi.These pad rollers are about 20.00 each and they have a pressed in oilite bushing at each end. Pad rollers are not supposed to turn constantly, generally only if a splics passes through. They should be set very carefully for two thicknesses of film. The MNR422's are metal and do have the internal shoulder. This shoulder is a few thousandths smaller O.D. then the outer shoulder is and will not touch the film. When pad rollers finally do wear out after many, many years of use it is possible for the inner shoulder to touch the film but a competant service engineer will never let them get this bad before replacing them. I have found the typical life span of the MNR422 to be close to 20 years!!

Mark
 

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Posted by Carl Martin (Member # 1146) on 10-23-2006, 06:29 PM:
 
but surely it is normal for a pad roller to turn if it is right before the upper loop or right after the lower one. if the pad roller is not closed, the loop will be lost. the only way for the pad roller to keep the loop is by contact with the film, thus it should turn. what am i missing?

i do prefer the metal rollers to the plastic, as we have at least one plastic roller with a flat spot.
 

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Posted by Mark Gulbrandsen (Member # 72) on 10-23-2006, 09:34 PM:
 

quote: Carl Martin

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but surely it is normal for a pad roller to turn if it is right before the upper loop or right after the lower one.

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