I recently got a "project camera" - ICA Reflex 3 1/4 x 4 1/4 SLR (model 756/1). The focal plane shutter and lens are good, but it is missing the mirror, the focus screen, and focus hood. The former two I can order from eBay with the proper dimensions, while the latter I will build.
If you happen to have the camera, would you be so kind to measure the dimension of mirror?