as promised, here's a couple of shots of the "Galiceno" pinhole with the shutter closed and then open.
I installed a tiny rare Earth magnet on the back of the shutter and on the face of the camera.
It acts like a pivot and keeps the shutter in place even when it's slid up and out of the way to make the exposure.
I don't know why I never thought of building them like this before. It's easy and works so well that I don't want to make cameras any other way now.