my profile | my password | search | faq & rules | forum home

» Film-Tech Forum ARCHIVE   » Operations   » Film Handlers' Forum   » CHRISTIE MUT -- Question about rollers (Page 1)

This topic comprises 2 pages: 1  2

Author Topic: CHRISTIE MUT -- Question about rollers Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 03-21-2003 03:57 PM                     I'm still trying to track down this back-tension problem I'm seeing with these MUT's... How many High-Speed Rollers is the Christie MUT supposed to have? Both of them? Or just the one at the bottom? For Clarification: High-Speed roller is the one with the race bearing (as opposed to the regular ones with just a nylon (?) sleeve).  |  IP: Logged Chris Markiewicz Expert Film Handler Posts: 209 From: Glenaviegh, County Tipperary, Ireland Registered: Aug 2002 posted 03-21-2003 05:07 PM                     Our Christie MUT has high speed rollers top and bottom with needle roller bearings, and no back tension problems. I did leave the brain spring bands in; when I removed them the run from the platter to the projector was bouncing too much. Distance from platter to projector is about 6 feet to allow the 16mm Eiki to slide in when needed.  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 03-21-2003 05:13 PM                     Manny, is your problem building up or breaking down? Chris, someone has been lazy and dragged their fingers through the 3 brain rollers to thread. That damages the rollers and causes them to wobble. It can also knock out any of the 3 digital formats from tracking properly. I would highly recommend you toss those and get new "green" rollers for your brain, then of course take that evil spring out.  |  IP: Logged Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 03-21-2003 06:34 PM                     Brad: The problem is with making up. The movies are VERY TIGHT -- I was actually called in to remove a centre ring that had collapsed completely during a fast buildup. That was an extreme case. Always, though, this tension results in a bulge that DOES NOT GO AWAY after regular showings/rewinding. I shudder to think it but it appears that film is being stretched slightly. I adjusted the speed controller so that the platter no longer goes at warp speed and I've personally built up movies with no problem by going to 6000' reels and using a low speed. No bulges on those movies. But the projectionists freaked when they saw how slow I was going. I was going unrealistically slow but my aim at the time was to narrow the problem down to the MUT itself and either speed or back-tension. Actually, Brad...now that I think about it...the problem is with break-down, too. I've been changing belts and re-tightening that big aluminum wheel a lot. What do you think? Could it be that I need two high-speed rollers and not just the one at the bottom?  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 03-21-2003 06:41 PM                        Having never seen a Christie MUT, I'm under the understanding that the belt gets dragged along while you build up. If this is the case, and you've been having to replace belts, I would expect that the belt is too tight and causing too much tension. What I do know for sure -- if the bulge doesn't go away after playing, the film has been damaged. Usually it's either sprocket hole damage or a stretched edge (or two). In this case it would be a stretched edge. Is it possible that whoever is building up prints has the MUT positioned so that the film has to twist through some excessive angles which would put more stress on one side of the film causing it to stretch?  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 03-21-2003 07:02 PM                     Manny, the problem isn't with the speed, it's your guys flipping the speed to 100% without "ramping" it up to speed. That is without a doubt what is creating your problem. Tell your guys to cool it and gradually increase speed. Also, building to large reels and then transferring to the MUT will make that issue mostly go away too. No one should be building from the shipping reels to the platter anyway. It's a poor film handling practice. On breakdown, when is the last time you checked the axle bearings on the decks? Are your center rings circles, or ovals? Also, are your guys flipping the speed up without ramping on breakdown too? That can cause the film to get "smashed" onto itself in the first reel. The newer rings have a latch, but for older rings, we usually stick a regular sized cd case in the opening as we takeup the last show. The cd case prevents it from collapsing. Are your MUT rollers black or green? Do they wobble?  |  IP: Logged Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 03-21-2003 08:03 PM                     The rollers are green. The MUT that I looked at today had wobbly rollers. The bearings had actually dislodged themselves from the high-speed roller and I had to replace it. After replacing that h/s roller I noticed a "bounce," which was due to the spindle being slightly bent. Not that I have a spare of that part, but I tried removing the spindle and found that I couldn't because it is currently frozen in place. The centre rings are round with a little gap that you squeeze to make it smaller when removing. It tends to collapse down to its smallest size when they build up movies. The other roller on the MUT (the top roller) is a bit ratty looking, too. But I couldn't replace that one because I didn't have one like it in my spares kit. That's when I started wondering whether that was the right type of roller in the first instance. Which leaves your question about the platter axle and bearings -- I heard a bad throbbing sound today as the speed increased. (Dare I say, the thing was purring?) I generally kept the speed down so as to eliminate that noise and hopefully some of that awful back-tension, too. It's been a while since that particular platter got a full shakedown and, after all, it is the one they seem to use all the time for their buildups. I will service the platter axle and bearings (and the little rubber tires) this weekend. Even if everything is fine, it would still be good to eliminate that as a possible cause.  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 03-21-2003 09:13 PM                        Since a collapsed center ring is no longer circle but oval, you're going to have uneven tension as you build up which will cause the film damage you are having. It might be a good idea to jam a cd case in there, to keep the ring circular, when building.  |  IP: Logged Paul G. Thompson The Weenie Man Posts: 4718 From: Mount Vernon WA USA Registered: Nov 2000 posted 03-21-2003 11:19 PM                     In my opinion, don't use standard rollers in place of high-speed rollers. There is a thread somewhere that has some pictures I posted where someone has done just that.  |  IP: Logged Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 03-22-2003 12:03 AM                     Daryl -- you're right (!) and the circle-turned-oval is probably what's causing the throbbing sound, too. This is one of the more interesting problems I've had to work on because now it seems like there are a lot of contributing factors. Paul -- are you saying that the Christie MUT uses two high-speed rollers? I'm still awaiting a definitive answer to that question -- is the adjustable roller a standard (nylon centre) one or a high-speed type (with bearings)? Oh...and Paul...you might consider changing that to read "Experience is inversely proportional to the amount of equipment ruined."  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 03-22-2003 12:12 AM                        quote: Oh...and Paul...you might consider changing that to read "Experience is inversely proportional to the amount of equipment ruined." Unless equipment is NEVER ruined that would be impossible! Since an inverse curve would mean that you've ruined less equipment as you gain experience, you would have to figure out some way to un-ruin equipment. Maybe "Experience is inversely proportional to the amount of equipment you remember ruining." would work.  |  IP: Logged Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 03-22-2003 12:29 AM                     I just KNEW that would take this thread off-topic. Let's try to focus on the problem, mkay?  |  IP: Logged Chris Markiewicz Expert Film Handler Posts: 209 From: Glenaviegh, County Tipperary, Ireland Registered: Aug 2002 posted 03-22-2003 04:16 PM                     Both our MUT rollers are green high speed with bearings.  |  IP: Logged Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 03-22-2003 04:38 PM                     Thanks, Chris.  |  IP: Logged Paul G. Thompson The Weenie Man Posts: 4718 From: Mount Vernon WA USA Registered: Nov 2000 posted 03-23-2003 12:25 AM                     OK Manny and Daryl....you win. Back to the subject. Yes, both should be high speed bearing type rollers. In addition to the speed, the loading is a little heavier during make-up and tear-down. Some of those roller pictures I posted some time ago were the standard rollers that were placed on the MUT for one reason or the other.  |  IP: Logged

All times are Central (GMT -6:00)

This topic comprises 2 pages: 1  2

Printer-friendly view of this topic

Hop To: Select a Forum: Category: Operations -------------------- Digital Cinema Forum Film Handlers' Forum Large Format Forum Ground Level Feature Info, Trailer Attachments & REAL Credit Offsets Category: Community -------------------- Film-Yak Film Handlers' Movie Reviews The Afterlife Bob Maar's Joke-A-Thon Category: Classified -------------------- Equipment and Supplies Wanted/For Sale Help Wanted/Seeking Employment Category: System -------------------- Software Beta Testing Forum

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.