Alpa Roto restoration/repair

[Bayliss]

I'm restoring an Alpa Rotocamera 6070 and I need to replace a the ring of rubber which moves the film, which has deteriorated on my camera - pictured below are my camera on the left and one in better condition on the right.



Does anyone familiar with these cameras know the thickness of rubber I should use for a replacement? I've contacted Alpa, but they don't have any info.

Thanks!

 

[bernard_L]

On the first picture, are we seeing the remains of the old rubber, turned into goo??
Is this a belt, driven by a pulley possibly on the other side of the camera? Or is it just there for proper operation of a friction drive?
From my experience (record players, audio cassette deck) it is sometimes difficult to find a rubber belt of rectangular cross section with the proper dimensions: thickness, width, circumference.
On the other hand, O-rings are specified by only two dimensions: major and minor diameter. It should be possible to find a suitable one. Maybe two or three side by side? Rule of thumb: installed belt should be stretched by 5%. There are several materials for O-rings, some more suitable (elasticity) for use as a belt.

 

[Bayliss]

On the first picture, are we seeing the remains of the old rubber, turned into goo??
Is this a belt, driven by a pulley possibly on the other side of the camera? Or is it just there for proper operation of a friction drive?
From my experience (record players, audio cassette deck) it is sometimes difficult to find a rubber belt of rectangular cross section with the proper dimensions: thickness, width, circumference.
On the other hand, O-rings are specified by only two dimensions: major and minor diameter. It should be possible to find a suitable one. Maybe two or three side by side? Rule of thumb: installed belt should be stretched by 5%. There are several materials for O-rings, some more suitable (elasticity) for use as a belt.

Yes, old rubber turned into goo, and it's just there for proper operation of a friction drive.

I was hoping I could just replace it with a strip of adhesive rubber (something like this: https://www.ebay.co.uk/itm/321612425946), which could be fitted without disassembling the camera.

 

[bernard_L]

Might work. Only way to know is to try
Also, might be good to make an oblique splice where the ends meet to help smooth rotation. Or place that at the "ends" of the panorama.

 

[Bayliss]

Might work. Only way to know is to try
Also, might be good to make an oblique splice where the ends meet to help smooth rotation. Or place that at the "ends" of the panorama.

Ah thanks for the tip, will definitely do an oblique splice

 

[Bayliss]

By the way - does anyone know how to set the angle of rotation for the auto setting when taking a picture?

The manual isn't very clear about how to do it