the entire back of the camera comes off with 4 knurled screws in the back. the film transport is four knurled screws (2 top and 2 bottom). three of these screws can be completely unscrewed. The 4th has a brass rod down the center and into the camera with a brass spade brazed to it the size of the hole and spade slot in a 120 film roll. It is permanently in the camera. ---
The film is fairly loose up and down, but has a wooden tray that has barely 1mm play in the film up and down where the image is made. At each end of this wooden tray is a slightly higher than the tray--about 2mm_- line of velvet that the film must pass over for a light tight seal. The rear of the camera includes a 1/32 inch piece of maple the width of the film tray and connected to the rear of the camera with foam. This keeps the film tight in the tray, and flat across the entire rear of the camera.