What causes film to chatter while playing?

"Richard Crowley" <richard.7.crowley RemoveThis @intel.com> wrote in message
news:dcb56s$1vp$1@news01.intel.com...
> "Doc" wrote ...
> > What is that causes film to chatter - the image jumps
> > around, projector makes that obnoxious clattering sound?
>
> One or more of these (and likely others, as well)....
> * Damaged film
> * Improper projector threading
> * Worn/damaged projector
> * Dufus projector operator

Thanks for the input, actually what I was hoping for is a more precise,
technical description of what's occurring.
 >> Stay informed about: What causes film to chatter while playing? 

"Richard Crowley" <richard.7.crowley.DeleteThis@intel.com> wrote in message
news:dcbc0h$58j$1@news01.intel.com...

> There are likely scores (hundreds) of things that could be
> causing this. It is not practical for either of us to speculate
> and try to list all of them. You will need to narrow down the
> discussion with some actual details of actual film and actual
> projector(s).

10-4.

In this case it's a GAF 1788Z dual8 projector running Kodachrome Std 8mm
film.

It doesn't happen all the time, just on occasion.

One thing I've noticed is that if instead of running the film onto the
takeup reel, I let it fall into a large (extremely clean) plastic tub, the
chattering goes alway altogether.
 >> Stay informed about: What causes film to chatter while playing? 

In article <G7cGe.10525$oZ.1511@newsread2.news.atl.earthlink.net>,
Doc <docsavage20.RemoveThis@xhotmail.com> wrote:
>
>"Richard Crowley" <richard.7.crowley.RemoveThis@intel.com> wrote in message
>news:dcbc0h$58j$1@news01.intel.com...
>
>> There are likely scores (hundreds) of things that could be
>> causing this. It is not practical for either of us to speculate
>> and try to list all of them. You will need to narrow down the
>> discussion with some actual details of actual film and actual
>> projector(s).
>
>10-4.
>
>In this case it's a GAF 1788Z dual8 projector running Kodachrome Std 8mm
>film.
>
>It doesn't happen all the time, just on occasion.
>
>One thing I've noticed is that if instead of running the film onto the
>takeup reel, I let it fall into a large (extremely clean) plastic tub, the
>chattering goes alway altogether.
>
>

Then is sounds to me (not an expert by any stretch of the imagination,)
is that your take-up reel mechanism is exerting too much 'pull';
enough that it's probably making the post-gate-loop slip, film pull past
the second sprockets, making the noise (sproket-slip,) and image jump -
the 'loss' of the post-gate-loop causing a fair amount of tension on
the film in the gate.

Note, however, I've never done anything with 8mm or Super8mm, and am
projecting 'down' based on past experience with 16mm film.

Leo Kerr
 >> Stay informed about: What causes film to chatter while playing? 

"Doc" wrote ...
> In this case it's a GAF 1788Z dual8 projector running
> Kodachrome Std 8mm film.

Does it also happen with Super8? On that projector,
what kind of adjustment/settings does it take to switch
between 8mm and S8? Is something with the format
changeover "slipping out of gear"?

> One thing I've noticed is that if instead of running the
> film onto the takeup reel, I let it fall into a large (extremely
> clean) plastic tub, the chattering goes alway altogether.

How much tension is the takeup reel pulling on the film?
Has the slip-clutch (or whatever mechanism?) become
"sticky"? Is it pulling too hard (and pulling the film right
past the claws in the gate)?

They traditionally used cloth bags (like pillow-cases)
to "dump" film into. Perhaps the soft surface isn't as
likely to scratch the film as a hard (plastic, etc.) surface?
 >> Stay informed about: What causes film to chatter while playing? 

"kerr leo" wrote ...
> Then is sounds to me (not an expert by any stretch of the imagination,)
> is that your take-up reel mechanism is exerting too much 'pull';
> enough that it's probably making the post-gate-loop slip, film pull past
> the second sprockets, making the noise (sproket-slip,) and image jump -
> the 'loss' of the post-gate-loop causing a fair amount of tension on
> the film in the gate.

That was my first guess, also.
 >> Stay informed about: What causes film to chatter while playing? 

If the film you are projecting is not old (old film shrinks and might
have a problem with sprocket hole alignment,) Then the problem might be
either take-up tension (Some consumer projectors used felt pads on the
take-up clutch & cleaning them with rubbing alcohol along with the
associated parts that press against the pads, might solve the problem.)
Other projectors used a spring compressed plate and fiber washer (sort
of like a Steenbeck edit machine take-up spindle assembly,) Again
cleaning the parts should solve the problem.
Another thing to check would be if there is a take-up tension adjustment
screw that can be loosened.
Also, make sure the film gate & pressure plate is clean, along with any
guide rollers the film comes in contact with.

Doc wrote:
> "Richard Crowley" <richard.7.crowley.RemoveThis@intel.com> wrote in message
> news:dcbc0h$58j$1@news01.intel.com...
>
>
>>There are likely scores (hundreds) of things that could be
>>causing this. It is not practical for either of us to speculate
>>and try to list all of them. You will need to narrow down the
>>discussion with some actual details of actual film and actual
>>projector(s).
>
>
> 10-4.
>
> In this case it's a GAF 1788Z dual8 projector running Kodachrome Std 8mm
> film.
>
> It doesn't happen all the time, just on occasion.
>
> One thing I've noticed is that if instead of running the film onto the
> takeup reel, I let it fall into a large (extremely clean) plastic tub, the
> chattering goes alway altogether.
>
>

--
Steven J. Rogers, C.A.S.
Warlock Sound - New York
 >> Stay informed about: What causes film to chatter while playing?