Film-Tech Forum ARCHIVE: brain roller tension problem

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Posted by Carl Martin (Member # 1146) on 12-16-2003, 07:56 AM:

so i took out the "springs" from the center rollers of the brains on our aw3r, since that's where our kelmar cleaner w/ filmguard normally resides. now there is too little tension, particulary when feeding through one of the brains. when winding the film onto the center ring, the film sags off the bottom roller (the second-to-last before running to the projector) a fair amount, hanging over either side of the roller's retaining bracket (don't know if that has a name). my coworker said it sagged all the way down to the floor for her. regardless, the sagging is bothersome. i took the roller off its shaft again and wiped off some excess oil, but it didn't seem to help. should i keep un-lubing that or is there some other issue?

tomorrow we're moving the cleaner upstairs so i'll be putting those springs back in for the time being. it's only 8' or so from the platter to the projector (forgot to measure, but it's way short of 15'), so the springs should not be necessary, right? but they are.

these are the christie-blue rollers on a v-leg aw3r. removing the springs upstairs from the black rollers on our aw3's has not been problematic.

any thoughts?

carl

Posted by Manny Knowles (Member # 1171) on 12-16-2003, 08:05 AM:

I have not yet seen the film sag at that particular roller.

But...what is the distance to your projector from the platter? That usually determines whether you want those springs left in or not.

Posted by Mark Gulbrandsen (Member # 72) on 12-16-2003, 08:57 AM:

Contrary to what some others on this forum may think there ARE very definately certain conditions that warrant use of the spring. Use of synthetic grease(Super Lube) on the spring will make for less long term problems if the spring is left in. Superlube is available from Ed Wolk as Century Gear Grease!!

Mark @ CLACO

Posted by Brad Miller (Member # 2) on 12-16-2003, 10:43 AM:

Pull the two flangeless rollers in the brain away from the center roller and see which one of them spins with amazing ease. Odds are it is the center roller and abuse over time has damaged the center hole. Just swap that roller with another one on the tree and watch your problems go away. Then teach the staff to make sure they don't push their fingers through the brain rollers when threading. That is the only thing I have seen that appears to cause that effect, but never have I heard of such a bad case of it.

Posted by Thomas Procyk (Member # 1170) on 12-16-2003, 12:16 PM:

Yeah, I had a similar problem when removing the springs. The film literally "flew" off the rollers and flapped around as if a fan was blowing on it. What's more, the brain did its "whipping" action going from 20 to 80 and back during payout.

This was because our rollers are fukked from the last animals (*cough* EFW *cough*) that ran the booth. Some are as warped as a record left in the sun. But we just spent $700 on parts this quarter, and our wonderful owner sprang for another film cleaner, so maybe in a few more months. [Smile]

=TMP=

Posted by Carl Martin (Member # 1146) on 12-17-2003, 04:06 AM:

i don't see how damage to the center hole would make the roller spin more easily. one of the brains has a wobbly center roller and the other has one which sits nicely. (only 2 brains for 3 decks) the brain with the nicely-seated roller has more of a problem with fast payout. i couldn't find any other blue brain rollers to try out. maybe i will cannibalize a black brain.

i had misunterstood my coworker. actually it was between the bottom roller of the projector and the platter tree that the film was sagging to the floor. it would be good to be able to bypass that roller when threading the platter, but in addition to conduit between the projector and the front wall, there is a mess of wires and conduit that the film would be running through and i'm not too comfortable with that.

what i'm mulling now is putting another roller between the projector and the platter, maybe 18" off the floor, for the film to ride over so it won't sag. there's no reason for anyone to be walking in that area when a show is running.

but for now the springs are back in. i cleaned them and the rollers and re-lubed them. they turn quite easily but not excessively. my reason for wanting them out was that i thought i was seeing very faint lines like rain in white areas of the image. sometimes it was rain, but i'm not sure it all was.

in situations where the springs should stay in (eg. >15' between platter and projector), is it simply not safe to run a film cleaner?

carl

Posted by Brad Miller (Member # 2) on 12-17-2003, 05:29 AM:

I wouldn't recommend running a film cleaner "dry" with the brain spring in. Of course running a film cleaner "wet" with FilmGuard doesn't pose any major issue with the added tension, nor would using PTR rollers.