Quote:
NOTHING TURNS THE FLYWHEEL OTHER THAN THE FILM. Some people do not seem to understand that!
Without the motion of the motor, the film will not turn the flywheel.
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| Elmo 16-cl fly wheel. How easy should it turn? https://8mmforumworldwide.com/viewtopic.php?f=13&t=1161 |
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| Author: | Roger Cathey [ Thu Apr 18, 2013 4:05 pm ] |
| Post subject: | Elmo 16-cl fly wheel. How easy should it turn? |
Would an incorrect tensioned fly wheel effect quality of sound and film tension and how easy should it spin? |
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| Author: | Dan Lail [ Fri Apr 26, 2013 5:33 pm ] |
| Post subject: | Re: Elmo 16-cl fly wheel. How easy should it turn? |
I think it should be prompted by the motor and spin freely even when the the motor stops, at least for a few seconds. |
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| Author: | Martin Jones [ Sat Apr 27, 2013 2:39 am ] |
| Post subject: | Re: Elmo 16-cl fly wheel. How easy should it turn? |
All flywheels on all sound projectors are completely free to turn. The ONLY influence that makes them turn is the moving film itself when held against the CAPSTAN (which is an extension of the FLYWHEEL) by the rubber PRESSURE ROLLER. The pressure roller is not driven by anything, but turns because it is in contact with the film. In fact, the pressure roller does NOT touch the capstan (flywheel) at all, only the film. When the pressure roller is released (during threading or when the machine is turned off), the film no longer drives the flywheel. The foregoing refers to a typical "Magnetic only" projector, where the Capstan/Pressure Roller combination smooths the passage of the film past the separate sound head. An Optical or Magnetic/Optical projector is slightly different. For "Capstan" read "Sound Drum". For "Pressure Roller" read "Idler Rollers".(sometimes called "Tension Rollers"). These do not press the film on the Sound Drum, they tension it so that it grips the Drum over at least half it's circumference. But the effect is the same; the film drives the Drum (flywheel). NOTHING TURNS THE FLYWHEEL OTHER THAN THE FILM. Some people do not seem to understand that! To test the freedom of the flywheel, remove the film, turn the machine off, make sure NOTHING is touching the capstan (drum).... and spin the flywheel by hand. If the bearings are good, it will spin freely and quietly for a considerable time. I have just done a check on my Eumig 810.... the flywheel was still spinning merrily after 6 minutes, and finally came to a stop after just over 13 minutes! The time taken is affected by the friction in the bearings and the balance of the flywheel. The latter can be assessed by the behaviour AFTER it stops. The degree of "out of balance" is demonstrated by the flywheel turning first one way , then the other, (and so on) before finally coming to rest Check also by feel that the pressure roller turns freely, with no stiffness; it's not heavy enough for a full "spin " test.. You can "spin" it, but it will stop fairly quickly, so you will not get any more information than you will by feel. Martin |
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| Author: | Erik Schoolcraft [ Tue Apr 30, 2013 10:45 pm ] |
| Post subject: | Re: Elmo 16-cl fly wheel. How easy should it turn? |
I have to agree and yet disagree with Martin on a few things. First, I've worked on hundreds of projectors and have never seen a flywheel leave any factory out of balance. Also, I've dealt with several 16mm projectors and from my experience, there is still either a pinch roller or an exiting sprocket that keeps tension on the film as it passes the sound gate of most projectors. My agreements with Martin's statements, you should be able to take the back off any projector and spin the flywheel easily by hand and I mean easily on every gauge of film. Super, regular 8 and even 16mm have very low breaking points so it shouldn't take much to spin them. Good news is that if you encounter much resistance than you can easily remove the flywheel and just grease the bearing or contact point where it is held in place. In 16mm I usually get roller bearings but smaller projectors usually have a fixed friction bearing. Either one takes a petrolium based grease and should be cleaned and relubed until it can be spun easily by hand. Also, you have to look at the pinch roller. If the rubber pressing the film against the flysheel roller is dried then you will not get good contact and the film will either slip or break under tension on any gauge film. I personally have a platoon of projectors both 8-super8-dual8 and 16mm. All my projectors use a pinch rubber roller that presses the film against the tension wheel. Keep in mind that some projectors have the rubber roller on the tension whell instead of the pinch wheel. What you need to do is first check the flywheel. If it is hanging up or stopping quickly after spinning it then you need to grease it. If you have rubber that is old and dry then it will look slick. Then best you can do it try to get something to strip a couple layers of the old rubber off to get to the soft stuff. I use Non-Slip Fluid that Radio Shack no longer carries but is nothing more than isopropal alcohol. Or my favorite poor man's fix is to take a wooden pencil's eraser and erase the bad from the good. Run it across the entire surface of the rubber roller and you should be back to new. |
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| Author: | Dan Lail [ Tue Apr 30, 2013 11:25 pm ] |
| Post subject: | Re: Elmo 16-cl fly wheel. How easy should it turn? |
Quote: NOTHING TURNS THE FLYWHEEL OTHER THAN THE FILM. Some people do not seem to understand that! Without the motion of the motor, the film will not turn the flywheel.
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| Author: | Julian Baquero [ Thu May 09, 2013 3:51 pm ] |
| Post subject: | Re: Elmo 16-cl fly wheel. How easy should it turn? |
I have an ELMO 16-AL, as far as I know it's a very similar machine to the 16-CL. When the projector arrived, the sound flywheel did not turn and the sound was horrible. I opened the machine and found that the transformer and the printed circuit under it where doing pressure over the the flywheel avoiding it to turn, I had to loosen the screws of the transformer and move it upwards as far as possible to free the flywheel, and then voila! Sound is amazing from then on. The parts inside the 16-AL are crammed together, there is very little space between parts, cables and circuits so it is good to take a look to see if something is in the way of X or Y part. As said before, the flywheel rotates only because of the film passing through, so there must be pressure between the capstan, the film and the flywheel roller. |
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| Author: | Martin Jones [ Sat May 11, 2013 8:36 am ] |
| Post subject: | Re: Elmo 16-cl fly wheel. How easy should it turn? |
"First, I've worked on hundreds of projectors and have never seen a flywheel leave any factory out of balance. Also, I've dealt with several 16mm projectors and from my experience, there is still either a pinch roller or an exiting sprocket that keeps tension on the film as it passes the sound gate of most projectors" Erik, I'm not suggesting that ANY manufacturer would let a machine out of the factory out of balance. But "out of balance" can occur if a machine is damaged (if a lead balancing plug becomes dislodged for example.. or grease drips onto the flywheel). I simply suggested the means of CHECKING for "out of balance". And, of course every machine has an "exiting sprocket"... that goes without saying (which is why I didn't say it!). It provides the motive power to the film. My discussion related to the means of ensuring that the film movement was imparted to the flywheel, the tension was maintained properly at the sound head or drum and that the flywheel operated properly. |
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