We finally located this long-awaited accessory - a tripod adapter that allows to use a modern (aka American) 1/4" tripod screws in the older 3/8" tripod sockets.

The adapter is made of nickel-plated brass, with a slot on the top. You can use a flat-head screwdriver to tighten it in your camera body.

The image shows a bottom plate of a Moskva camera with and without the adapter. The camera is for illustration only and is not included.

Buy several and install them on all your cameras.