I finally found the right place to put the pinhole in my Agfa Box without resulting with vignette.
It would be perfect if it wans't the white spot that came out in the middle of every frame.
I guess it is the reflected light from the pinhole Metallic part, bouncing lighting on the glass in front of it that bounce the light back into the pinhole.
The only way to correct 100% seems to taking the glass of the camera out.
But just in case I am missing something I would like to know about others here opinion about what is causing it and its and correction.
Here an example from a self: