ARRIFLEX with turret : 16ST, 16M, 35 - Correcting focal flange depth

[Stéphane Mandelkern]

Dear all,

On Arriflex with turret (Arriflex 16ST, 16M, 35xx), when you check the focal flange depth and find a wrong depth, what is the solution to correct it.

Thank you in advance.

Stéphane

[Dom Jaeger]

Generally you shim under the gate assembly, but then you need to check and possibly adjust the ground glass depth too. 
 

I just found this site with repair manuals including one for the 2B/C and links to my own cinetinker service posts:

https://learncamerarepair.com/productlist.php?category=2

You do need to have an Arri depth gauge kit (gauge, 52.00mm blank, and backing plate), and it certainly helps to have a collimator for the ground glass adjustment, otherwise a perfectly calibrated test lens is essential.

[Stéphane Mandelkern]

Thank you very much Dom, for this site.

I had already read precisely your posts on Arrriflex 16st and Arriflex IIC on your cinetinker site. They are my bedside books. But I didn't know the Arriflex II service manuals. The three talk about measuring FFD but not adjusting it.

In fact, I dismantled the turret of my Arriflex 16M and found a couple of very very thin washers. I thought maybe there were the mean of adjusting the distance of the whole turret from the body and thus from the film plane.

Do you think so ?

[Dom Jaeger]

It's been a few years since I worked on an Arri 16S but my recollection is the turret has a set distance for the lock screw to seat on the stepped pivot shaft so that the turret can rotate but there should be no axial play - ie the turret should not be able to move away from the film plane even slightly. I don't think there is room to shim the turret without making it stiff to turn. Shims may have been added if there was some axial play in the turret, but they should not have been used there to adjust flange depth. That is done by shimming under the mechanism. See picture #32 in my Arri 16St Service blog, where you can see the silver shims that were used to set the flange depth on that particular camera. I actually mention them in the blog:

http://cinetinker.blogspot.com/2019/02/arri-16st-service.html