Film-Tech Forum ARCHIVE: Damage when projector is left closed?

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Posted by Keith Peticolas (Member # 971) on 09-05-2005, 06:22 PM:

Howdy film gods. I have 6 Century SA's and one child projectionist who believes leaving the projectors in the closed position overnight is not damaging. What is the exact damage we can look foward to because of this? This is being done on an almost regular basis.

Posted by Steve Guttag (Member # 268) on 09-05-2005, 06:28 PM:

Keith, define "closed" Do you mean the gate? If so, is it a single lens or turreted machine?

The general rule on all sprung devices (not just gates) is to leave sprung things in their most relaxed state to minimize them wearing out.

As to the Century gate...if it is a single lens system...I've had more trouble with the closer spring than the tension bands. As such, I leave a single lens Century gate closed overnight...for turrets, I leave em open.

Posted by Keith Peticolas (Member # 971) on 09-05-2005, 06:38 PM:

Thanks Steve, single lens. I meant by leaving the pads/rollers down on sprokets and gate engaged. Was always drilled into me that this was kiss of death.

Posted by Steve Guttag (Member # 268) on 09-05-2005, 07:04 PM:

The pad rollers couldn't care less...the are in a bi-stable arrangement so either open or close are equally non-stressful...the gate, I would leave closed...the SG-14 spring is more likely to wear out faster than the SH-1811 tension bands from being pressured over night. Arguements can and have been made both ways here...I speak from personal experience and preference...you findings may vary.

Posted by Keith Peticolas (Member # 971) on 09-05-2005, 07:20 PM:

Thanks again. Will put it in the consideration hat.

Posted by Dustin Mitchell (Member # 372) on 09-05-2005, 07:58 PM:

We've always left everything in the open position. Never heard the tension reason before, I'd always thought it was a courtesy for the incoming projectionist the next day.

Posted by Brad Miller (Member # 2) on 09-05-2005, 09:26 PM:

On most machines, leaving things closed is better. (Christie projectors are the first exception I can think of, as they are happier left open.) Again as Steve said, you want the springs to be relaxed. I have yet to have a problem with gate bands wearing out on ANY machine. This assumes you are keeping your prints properly lubricated though. Theaters that don't will find that not only will their bands wear faster, but their sprockets will get hooked significantly faster.

Posted by Mark Gulbrandsen (Member # 72) on 09-05-2005, 10:02 PM:

quote: Brad Miller
I have yet to have a problem with gate bands wearing out on ANY machine. This assumes you are keeping your prints properly lubricated though. Theaters that don't will find that not only will their bands wear faster, but their sprockets will get hooked significantly faster.

I'll back up Brad on that statement. Film Guard DOES make a huge difference in preventing gate band wear. Theatres that I service that use FilmGuard never replace bands... well ok, after three or four years of use!! Theatres that don't use it need them every year or sooner. Christie bands are extremely thin and wear even quicker, sometimes needing twice yearly replacement to maintain picture good steadiness and to keep dust levels down.

Mark

Posted by Brad Miller (Member # 2) on 09-05-2005, 10:20 PM:

Nope Mark, I have NEVER had to change bands in a FG theater. EVER! If you are seeing that at your theaters, then the staff isn't really using the cleaners religiously once you walk out the door. I only see pictures getting steadier as time goes by, regardless of projector model.

Posted by Jason Whitlock (Member # 3077) on 09-06-2005, 12:15 AM:

on our Christie M35GP's we open the gate and the ultramittent shoe.. and leave all the pad rollers closed as those stupid horseshoe springs that break easily are relaxed in that position.

Posted by Monte L Fullmer (Member # 2797) on 09-06-2005, 01:14 AM:

Okey, let's drift over to the Simplex 35, or commonly know as the "XL" head: Trap and Gate open, or closed during the night? Normally, I open the trap and gate, but was wondering on the massive spring that keeps the gate closed to whereas I now keep the gate closed at night. Would it then be the same as the "SL" machine?

Christie - Christie 35 and the P35GPS machines, I always left the gate swung open being no spring pressure to keep it closed.

..and the same with the Cine V5 machines. But closed on the V8's.

-Monte

Posted by Brad Miller (Member # 2) on 09-06-2005, 04:00 AM:

You've got it right Monte.

And yes, the XL - leave it shut.

Posted by Mark Gulbrandsen (Member # 72) on 09-06-2005, 07:50 AM:

quote: Brad Miller
If you are seeing that at your theaters, then the staff isn't really using the cleaners religiously once you walk out the door.

Although quite a few locations buy FG I am lucky if they ACTUALLY use it... to much like work ya know for todays kids....

Mark

Posted by Mark J. Marshall (Member # 1409) on 09-06-2005, 08:45 AM:

We actually do keep things Film Guarded religiously at our theater, and come to think of it... you're right, our bands are in excellent shape. I had to replace a couple when I started a few years ago because they had dings on them, but haven't replaced any since. I never put the two together.

For what it's worth, we open everything every night on our Simplex 1050s.

Posted by Gordon McLeod (Member # 33) on 09-06-2005, 09:08 AM:

In the theatres we service we recomend the trap be left closed at night with the trap door removed that way the closure springs are left relaxed and the bands are left with no pressure on them as well
I preffer the pads left open and the pinch roller on the sound drum must be left open

Posted by Andy Bergstrom (Member # 360) on 09-06-2005, 10:33 AM:

Using the relaxed spring therory, should intermittant pad shoes that are spring loaded be left open at night also?

Posted by Keith Peticolas (Member # 971) on 09-06-2005, 01:23 PM:

Wow. Okay now I stand corrected. Thanks for the input guys, will put it to use. And we are faithful FG users up here, so that is a big help.

Posted by Monte L Fullmer (Member # 2797) on 09-06-2005, 01:24 PM:

Okey, side topic of closure: how many of yous lace the machines up at the end of the night for the next day's operation?

...which I can't stand [Mad]

!

-Monte

Posted by Keith Peticolas (Member # 971) on 09-06-2005, 01:26 PM:

Nope, you run the show, you thread the show.

Posted by Dick Prather (Member # 1136) on 09-06-2005, 01:35 PM:

It seems like I have seen this discussion here before. I have been leaving everything open for many years with no problems. I was told to do that when I started to keep pressure off the film path parts and help remind to clean the machine before we left. We used to clean everything before leaving and have the machines ready for the next days show.

I always kept a spare SG-14 for Century's but only replaced a couple of them due to breakage. Never had to replace the XL or any other Simplex gate spring.

Gordon probably has the best solution providing the gates are not dropped. Pad rollers can go either way and the sound drum roller must be left open if they can be. Intermittent shoes, if separate, were left open. It's probably what you are most comfortable with that doesn't damage the projector with the importance of keeping them clean and in good condition.

Dick

Posted by Brad Miller (Member # 2) on 09-06-2005, 02:59 PM:

quote: Keith Peticolas
you run the show, you thread the show.

I'll add to that my personal rule. Not only is the person running the show responsible for threading it, but he is also responsible for making sure the film is running through the cleaner (every show) and it is his responsibility to clean the projector and film path to meet minimum requirements set before each film is ran.

I converted to this ruling years back because I had problems with someone throwing the film in a dusty projector after a screening of a new print the night before and blaming it on the closing projectionist. That's no excuse, so now it's whoever threads the machine's responsibility, although I do consider it courtesy for the closing operator to rewind the media pads and clean the projector if he did a screening of a new film. (If it was just a regular run of a print, there is no real need to clean the projector since they stay clean.)

Posted by Monte L Fullmer (Member # 2797) on 09-06-2005, 03:52 PM:

I used to get bounced on when I didn't thread up the night before when I started back in '02. I told them to shove it where the sun don't shine since I told them, flat out, that this is not in my policy of booth operations. Then I tell them that if I thread up the night before, then something goes snafoo, then the finger is on me. No finger is going to get pointed at me when I leave the place with the machines being "put to bed" every night - empty.

This is what I tell these clowns that I work with in other theatres, that if you thread up the night before, it'd be your fault if something happens on the next day's opening, being that the openers doesn't bother to check anything, and since they love to thread in a hurry just to get out of the building as fast as they can - no cleaning (shee, what's that...??) whatsoever ...

And they wonder why I'm such a grinch and sometimes a very nasty prick when I visit their theatres ... but it doesn't sink in since they don't care. [Mad]

(Now, you wonder why I really want to leave and get back to a more professional operation.....)

-Monte

Posted by Olivia Coleman (Member # 3193) on 09-07-2005, 02:06 AM:

quote: Monte L. Fullmer
how many of yous lace the machines up at the end of the night for the next day's operation?

Thread it the night before?!?! What, and get dust on the print?!?! NO WAY! [Wink]

Posted by Monte L Fullmer (Member # 2797) on 09-08-2005, 01:35 AM:

Yes Olivia, they've been doing this since day one - lacing up the night before since the opening manager is the operator and only has an hour to get downstairs ready and the other help doesn't come in till almost when the boxoffice opens - and the company whines with extra help coming in, thus driving up payroll.

Also, if the opening manager, who is usually a hourly person, comes in any earlier to take a slower pace in as well as lace up the machines, then up goes payroll again, a red flag pops up and the company whines again about increased payroll.

It's a no-win situation with these conditions.... [Frown]

Thus, I have to "clean up" their mess that they won't do.

-Monte

Posted by Daryl C. W. O'Shea (Member # 1303) on 09-08-2005, 01:46 AM:

Wow, you know a company is cheap when they won't spend at most 90 seconds a screen (you can clean the machines the night before, like you should anyway, instead of threading them) to thread up at the start of the day.

Posted by Phil Blake (Member # 2012) on 09-08-2005, 06:53 AM:

The way we always did it was ;

At the end of the last session , open up machine clean it and leave all sprung parts in the relaxed state.

At the start of the first session , run machine for a few minutes , and then thread it up.

Posted by Monte L Fullmer (Member # 2797) on 09-08-2005, 01:50 PM:

quote: Daryl C. W. O'Shea
you know a company is cheap when they won't spend at most 90 seconds a screen...

Yep, pretty bad and I've even mentioned it to each manager, and with the massive amount of opening procedures that the person must go through, it practically leaves no time for time to be spent upstairs (which I don't believe).

Plus at closing, it's a race to beat it out of there - sometimes to where the bulb hasn't had the time to cool completely before main power is turned off. I've caught a few of these theatres shutting down the consoles right afte show end and the bulb is still glowing red hot. I jumped on them hard about this to leave the console on until that bulb has completely cooled down.

Hey, when you have kids running things and the manager is among that group acting like one, .... you can see what I have to go through now ........

quote: Phil Blake
At the start of the first session , run machine for a few minutes , and then thread it up.

Hmmmm, I used to do this at a drive-in in the early pring and late fall when the machinery was pretty cold.

Never did this due to the unnecessary wear on the machines for the indoor houses.

-Monte

Posted by Dick Prather (Member # 1136) on 09-08-2005, 02:06 PM:

Every start of a shift we did the following:

Turned on the sound system and lights.

Checked all oil levels before turning machines over.

Gave each machine a visual look over.

Thumped the sound with a card on each machine.

Rotated by hand both machines to make sure nothing was binding.

Made sure everything was clean and ready to go.

Turned on motors to let machines run for a few minutes.

Go about your other business with film, etc.

Never had any problems with this.

Dick

Posted by Brad Miller (Member # 2) on 09-08-2005, 02:56 PM:

quote: Monte L Fullmer
I've caught a few of these theatres shutting down the consoles right afte show end and the bulb is still glowing red hot. I jumped on them hard about this to leave the console on until that bulb has completely cooled down.

That's why in this day and age you MUST install time delay relays to keep the blowers running because I have seen kids popping the breakers as the last few feet of film is still coasting through the projector. The extra time and expense to add time delay relays pays for itself anyway with bulb saving costs in less than a year's time.

Posted by Mark Gulbrandsen (Member # 72) on 09-08-2005, 03:11 PM:

I can't believe the concern over spring conpression on this thread. One might be concerned if one only ran on weekends and just a few shows at that but most chain theatres are off screen for 8 hours or less and spring set doesn't really even come into play in these circumstances......

I agree with Brad on the delay relay thing... excellent idea!! Some of our customers do this and some don't want to spend the $$... even if you tell them in plain english how much they will save. Sadly many are not smart enough to realize the savings of extended cool downs over just one years time, all they look at is the bottom line on construction costs!!

quote: Dick Prather
Rotated by hand both machines to make sure nothing was binding.

Dick,
I always did that sort of thing to and trained newbies to do that "Pre Flight Check". One time it paid off big when I discovered that a union operator had placed the flyball governer head down into the gear train in a BX-80 in a botched attempt to slip up both myself and the theatres new owner, the gear train woulda striped badly! A gentle turn on that machines motor by hand and I could easily feel it in there. All proof the owner needed to send the union guy walking was in the design of the machine itself in which the governer head is too close to the back cover to have fallen off [Big Grin]

. Appropriately, the Union shortly thereafter relinquished that location completely over to the non-union owner when he presented obvious proof of of what the operatior had done the union's buisness agent..... I also believe that projectionist was out of a job as well after that episode [thumbsup]

!! Had he left it alone and let us just do the booth work as we told them we were going to do he'd probably still be employed there today.... After that episode the Union left me alone and never once hassled me on any job that I did.

Mark

Posted by David Buckley (Member # 2600) on 09-09-2005, 01:22 AM:

quote: Mark Gulbrandsen
... I can't believe the concern over spring conpression on this thread. One might be concerned if one only ran on weekends and just a few shows at that...

ooh - thats me then. On a Century clone, what should one do?

Posted by Monte L Fullmer (Member # 2797) on 09-09-2005, 02:44 AM:

Keep the trap closed then on that Clone - be it a Monee, or a Westrex you have. - Monte

Posted by Gordon McLeod (Member # 33) on 09-09-2005, 10:23 AM:

I always insist that projectors be run for about 5-10min before they are threaded at the beginning of the day to get oil pump through the machine and belts to loose any set developed overnight

Posted by John Pytlak (Member # 331) on 09-09-2005, 11:33 AM:

At the Grandview drive-in, we always ran the unlaced projectors for about 10 minutes prior to the evening's shows. Especially important in the cool spring and autumn months.

Posted by Mark Gulbrandsen (Member # 72) on 09-09-2005, 03:33 PM:

quote: Gordon McLeod
I always insist that projectors be run for about 5-10min before they are threaded at the beginning of the day to get oil pump through the machine and belts to loose any set developed overnight

This is far more important that opening the trap and pad rollers at night!!! This in fact is the ***BEST POINT MADE*** in this whole thead so far. Not only do belts take a set but the grease in ball bearings, oil in movements and shafts also falls back to the bottom of the bearing, sump or movement. A 10 min run in and intermittent shaft oil spirals, sprocket shaft oil spirals all get pre-oiled and brought somewhat up to normal operating temperature in this time. This film of oil will prevent a ton of wear on these critical parts and they will last far longer.

The above example is one of the best examples I've seen here in ages of the difference in thought of a well seasoned "Chief Projectionist" and someone that just claims to be one or was handed the title [thumbsup]

.

Mark

Posted by Monte L Fullmer (Member # 2797) on 09-09-2005, 03:44 PM:

quote: Mark Gulbrandsen
A 10 min run in and intermittent shaft oil spirals, sprocket shaft oil spirals all get pre-oiled and brought somewhat up to normal operating temperature in this time....

...and why I hate lacing up the night before for this very reason. We can also include the platters on this - "warm" them up a bit by letting the motors spin and get the tires back to round, especially the AW3 units.

One laces up the night before, faces a risk that something MAY not take off. And if that happens, then you have a mess to unlace the machine and platter and find a way to move that print to another deck if the ring has already been pulled, epsecially if that theatre doesn't have a "pizza board" to move the print.

Why make hell for yourself each opening day....

(Then, I heard of idiots saying by turning on the bulb for a couple of minutes "warms" up the bulb for the day. I put a screeching halt to that one real quick.....)

thx-Monte

Posted by Dustin Mitchell (Member # 372) on 09-09-2005, 10:03 PM:

I'm confused about something here. The consensus seems to be that running the projectors for 10 minutes at opening reduces wear....but how? What's the difference if the projector is run for 10 minutes with or without film in it?

I can see the reasoning for perhaps getting a steadier picture by doing this but I'm confused about how exactly it reduces wear.

Posted by Gordon McLeod (Member # 33) on 09-09-2005, 10:14 PM:

My analogy is one shouldn't get in their car and start the engine and drive out with out letting it run for a few minutes first to warm it up especially on a cold day and a projector is built to much tighter tolerances

Posted by Daryl C. W. O'Shea (Member # 1303) on 09-09-2005, 10:42 PM:

Putting more load (as in making it pull film) than necessary on a machine before it lubricates itself and gets to its normal operating temperature is always going to create more wear than the little wear you'll cause by "warming up" such machine while unloaded.

Anyway, as Gordon said, in addition to getting the oil moving, belted machines get any belt set out of them before an increased load is put on the belts. This will (1) make your belts last longer and (2) give you time to change the belt if it breaks as belts are far more likely to break after they've been idle and set than any other time.

Anybody that works for me that refuses to warm up a machine won't be working for me very long.

Posted by Dustin Mitchell (Member # 372) on 09-09-2005, 11:06 PM:

The car analogy doesn't make much sense to me. When you put your car in gear and drive it the engine is under the extra stress of 4,000 pounds it has to move. Higher tolerance or not a projector isn't under nearly that much stress. How much extra load does pulling film through a projector create though, especially on a platter machine?

I mean, if I'm wrong I'll accept that no problem, but honestly how much more stress doe the gears/belts have on them with film running through the projector as opposed to without?

Posted by Daryl C. W. O'Shea (Member # 1303) on 09-09-2005, 11:09 PM:

Depends on the design of the machine and its intermittent. To find out you just have to listen to it with and without film.

Even if there were no difference, you'd be far better off to have something break, either a belt of gear tooth, without film in the machine.

Posted by Mark Gulbrandsen (Member # 72) on 09-10-2005, 04:25 AM:

quote: Daryl C. W. O'Shea
Anyway, as Gordon said, in addition to getting the oil moving, belted machines get any belt set out of them before an increased load is put on the belts.

Well, Daryl, there is one exception to that one... the RCA Penthouse! The belt set-in is going to be so bad in that POC that you will need a new belt with each show!!

quote: Dustin Mitchell
The car analogy doesn't make much sense to me. When you put your car in gear and drive it the engine is under the extra stress of 4,000 pounds it has to move. Higher tolerance or not a projector isn't under nearly that much stress. How much extra load does pulling film through a projector create though, especially on a platter machine?

Dustin,

Well, Not running a machine first hand unloaded DOES create extra wear. New US built machines typically run with .001" of tolerance or less in the intermittent.... thats the only area of any "real" tight tolerance in US built machines other than the sprockets, the rest is as sloppy as it gets...really! There are European machines that DO run tolerances of .001 on sprocket shafts, oil pumps, etc.... and many of the well made European projectors like the Phillips and Bauer projectors had manufacturing tolerances of 1 micron on some of the intermittent parts. Now thats ***extremely*** tight tolerance and quite amazing craftsmanship and also why many of these projectors are still in use today and very popular!!

At LaVezzi Precision where all the stars and cams are made for US built projectors the final grind on the slot is so very slight that these grinding operations are carried out in sound proof rooms and the grinder spindles run on air bearings!! The operator at most hears a slight tick when the wheel passes through the slot, many times there is no sound at all that is audible. The star is indexed to the next slot by a super high presision jig that LaVezzi custom built in their shops... All jigs like this have to be custom made to achieve this sort of high tolerance... ya can't buy this tooling off the shelf! A tour of LaVezzi is without doubt the most amazing tour that a film technician can go on and you can't begin to appreciate the quality that goes into each part they manufacture without seeing it done first hand.

When compared to a car engine some of the parts in an intermittent are proportionately under as much stress as some parts are in car engines. In a Simplex for instance you have a cam pin that is just .1" in diameter running in a slot thats also just .1" in size when new and you develope perhaps .0001 extra for some oil film in there to lubricate the pin and slot. After many thousands of hours this is the place that a movement will show the most wear and sometimnes you will hear noise generated by a loose fitting cam pin as a very audible annoying clickity clack, a really worn Century movement can actually sound like a machine gun!! The slot and pin are considered no tolerance parts at manufacture but with proper run in these parts DO develop just enough clearance for an oil film to lubricate them. Also the machining marks developed from grinding the slot in the star also assist in carrying oil to libricate this almost zero tolerance part. So not only is there basically no clearance but there is ***BARELY*** any clearance for ***ANY*** oil to cushion these parts. This is the main reason why its imperitive to use the correct weight oil!! On top of all this you have the odd angles of attack that the pin is at whilst the pin is traveling though the slot and pulling the typically 6 to 10 oz pull down load of ***EACH*** frame of film ..... and this is happenning 24 times a second!! On a really worn star its easy to see where the points of maximum load occur because the walls of the slot actually develope waves in them! Whilst the star wheel is at some of its extreme angles the equivelent weight increases and can be the equivelent to pulling hundreds of pounds equivelent weight in an fraction of a second. So without any film of oil present on shafts, spirals and the cam pin they essentially run dry for a 10 to 15 seconds whilst doing the job of pulling hundreds of pounds!! Keep in mind that the 100's of pounds is an estimate on my part but I doubt that anyone here wold dispute that figure... I'm not a mathamatician but I believe that Daryl would get that answer if he ran the problem through his Eniac Computer!!

BTW: a platter fed machine does place ***LESS*** stress on feed and holdback sprockets and their shafts than does a properly operating reel to reel system running the typical 1 hour reels(sorry Steve G. but this is true). A properly operating large reel transport such as a double mut places about the same operating stresses on sprocket shafts and sprocket teeth as a platter system does.

Hope this helps but I've probably got you really confused now....

Mark

Posted by Dustin Mitchell (Member # 372) on 09-10-2005, 05:53 AM:

I got all that, and thank you for the info. I knew that projectors were built to very fine tolerances but I had no idea.

Daryl's point about things breaking without film running is certainly valid. Honestly its not that much extra work to do dry runs on the machines. Assuming you power up at the console you could start each one as you powered up the projector. By the time you powered up the last projector the first one would have run long enough and be ready to load.

Anyway, just as a general point of curiosity I still gotta wonder how much extra stress the film running through the projector really causes. Is there any data on this?

Posted by John Pytlak (Member # 331) on 09-10-2005, 07:17 AM:

Even the few ounces of back tension the film puts on the intermittent sprocket translates to some pretty severe forces on the starwheel and cam pin.

Posted by Mark Gulbrandsen (Member # 72) on 09-10-2005, 08:20 AM:

quote: Dustin Mitchell
Anyway, just as a general point of curiosity I still gotta wonder how much extra stress the film running through the projector really causes. Is there any data on this?

There would be a huge number of different factors to combine into an aquation to determine this. That equation would probably fill several blackboards by the time you were finished! From back tension, duration of pull down, metal hardness, size of the parts involved, the time pull down takes, the differing angles of which each angle would of course have its different wmount of induced force so that part would be logrithmical, etc. A heck of alot of factors wold be in that equation! Let us know after you've worked it out [Wink]

quote: John Pytlak
Even the few ounces of back tension the film puts on the intermittent sprocket translates to some pretty severe forces on the starwheel and cam pin.

John,

You're amazing. You translated exavtly what I was trying to say above your post into just one understandable sentance [Razz]

!!

Thanks,
Mark

Posted by Daryl C. W. O'Shea (Member # 1303) on 09-10-2005, 09:17 AM:

My brain hurts just thinking about thinking about it. To give you an idea though...

A freewheeling intermittent spins extremely easily. There's little force on the cam.

Now add a few ounces or so of force due to the film. Since the intermittent cam exerts most of its force halfway into the slot you're going to see about 75-100% of that force (from the film), depending on the size of the intermittent, exerted on the cam.

So... you've added a few ounces of drag force, up from almost nothing before. As the amazing John and Mark would say, that translates into a huge increase.

Of course, if someone has access to MSC.ADAMS (or has $10,000 to renew my license) they could simulate it and find out the exact numbers. It might be cheaper to just buy Evans Criswell lunch though. [Smile]

Posted by Steve Guttag (Member # 268) on 09-10-2005, 09:22 AM:

I don't think the equations would fill blackboards up (depending on your black board size). Using a bit o calculus and properly expressing the forces and such...but lets cut to the chase...

Take a projector that has sat all night (particularly in the cold)...and try turning the flywheel. Spin the machine by hand for a few cycles of the intermittent.

Now, run the machine for 5-10 minutes.

After that, turn the flywheel again for a few cycles of the intermittent. You will (or should, since I always do) feel that the machine turns notably more free. Now, remember the motor on the projector is, more often than not, given a mechanical advantage in its gear ratios...any part of the projector that does not have a favorable gear ratio (in Century projectors, everything but the sprocket shafts) feel the differences more!

Next day (or on a different projector within the complex)...thread the film before turning the machine on...take a feel of the flywheel with the machine cold with film...it will be turning more stiff than the non-film machine.

I can' think of the time where the first thing I did in a theatre was to turn the machine over by hand FIRST...just to feel how it is doing and to listen for anything out of the ordinary. Then check the oil level and add oil/grease as necessary (machine dependent)...once all of that is satisfied...run the machine for at least 5-minutes without film (typically during this warm up time, I'll talk with the manager about anything to note about the day's events)...then thread up the projectors.

Oh and reels never hurt anything [Razz]

Posted by Mark Gulbrandsen (Member # 72) on 09-10-2005, 11:38 AM:

quote: Steve Guttag
Using a bit o calculus and properly expressing the forces and such

Calculus wold undoubtdly play the key roll in determining the forces and such but you also have to come up with the forces at all angles of the cam pin and the forces of the film at all angles and place that into the rquation as well. Since this is a pin entering a variable revolving slot the angle constantly changes and is quite logarathmic as is evedenced by the wavey type wear of the slots in many movements..... Some place I have a book that shows the pull down cycle of star wheels with differing pin entry angles. I believe that recent Kodak Star Wheel patent also may show that, this book I have may also show one very similar to the Kodak design.

Mark

quote: Daryl C. W. O'Shea
It might be cheaper to just buy Evans Criswell lunch though.

Excellent idea [Cool]

!! Heyyyyyyyyy Evanssssss....... where you at dude......

Mark

Posted by Jeffry L. Johnson (Member # 453) on 04-07-2006, 07:20 PM:

quote:
Please help out our managers by threading up as many of the movies as you can at the end of the night. I know the concern about getting blamed for problems, but the projectors are checked over before they're started. Having all or most of them threaded just makes it easier for the people opening at the end of the night. [sic]

I don't want to do this, but management wants it done. So it seems that I'll have to. It's their equipment and their managers running the opening shift the next day.

Posted by Eric Robinson (Member # 2966) on 04-08-2006, 12:54 PM:

And of course in a perfect world the gate and trap closing distance would be set perfectly and the intermittent shoe pressure would be set perfectly.

There are cases; however, when the gate and intermittent shoe adjustments are in error which produce extremely high pressure on the projector when it starts up.

Posted by Luci Reeve (Member # 3651) on 04-08-2006, 03:43 PM:

1. Leave the gate and pad rollers closed at night.
2. Run the projectors 5 minutes before threading up.
Are these the recommendations for a Century C projector?