Bolex D8l rubber roller question

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freddenacka
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Bolex D8l rubber roller question

Post by freddenacka » Sat Jul 12, 2014 3:22 pm

Halo
Should this one be able to move?
It is stuck in my d8l but can move in my L8
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cameratech
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Re: Bolex D8l rubber roller question

Post by cameratech » Sun Jul 13, 2014 12:47 pm

It should turn clockwise but not anti-clockwise, ie it shouldn't turn as film passes over it but act as a break.
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SurlaCraque
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Re: Bolex D8l rubber roller question

Post by SurlaCraque » Tue Jul 15, 2014 12:46 am

In my B8VS it doesn't spin at all. Kinda suspecting it's not supposed to, but I don't know much about these cameras.

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BAC
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Re: Bolex D8l rubber roller question

Post by BAC » Tue Jul 15, 2014 4:59 am

I don't think it rotates on some of the older versions.

Rob
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Re: Bolex D8l rubber roller question

Post by Rob » Wed Jul 16, 2014 2:31 pm

That roller (or more appropriately, post) shouldn't turn. Its there to stop the film being tugged through the gate. The takeup spool is driven by the motor. As film runs through the camera the circumference of the film held on the takeup spool increases so a single rotation of the takeup spool draws progressively more film onto it. At some point the amount being pulled onto the takeup spool will exceed the amount being passed through the gate by the claw. At this point the takeup spool will pull on the film and for that reason the takeup spool has a slipping clutch under it. The tension on the film causes the clutch to slip and the film is then loose again. The rubber post is there to stop the tension on the film being applied to the claw. As the takeup spool pulls the film tight, the rubber post grips the film causing the clutch to slip. In this way no pressure is applied to the claw and the normal passage of film through the gate is unimpeded.

On later models (LA, P, S models) the rubber post is actually a roller and can rotate, but it can only rotate in one direction: backwards. These cameras have a backwind handle which allows short lengths of film to be pulled back through the gate then reexposed for making dissolves between shots. If these cameras had the rubber post it would not be possible to pull the film back through the gate, the post would grip it. So the post is replaced by a roller with a ratchet which allows the film to move backwards when the backwind handle is turned. The mechanism works in exactly the same way as the earlier models when he film is running normally through the camera.

As for your L8..... I've no idea. It doesn't have a backwind handle so far as I know the post shouldn't rotate in either direction..........

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MIKI-814
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Re: Bolex D8l rubber roller question

Post by MIKI-814 » Wed Jul 16, 2014 3:11 pm

SurlaCraque wrote:In my B8VS it doesn't spin at all. Kinda suspecting it's not supposed to, but I don't know much about these cameras.
Thank God. I thought my B8 was the only one VS on Earth 8)

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