filmholder adapter
Instead of making an entire new 4×10 back for my 5×12 camera, I just made an adapter the size of a 5×12 holder that the 4×10 holder fits into. This allows me to shot either format with the one back. Since the new 4×10 holder’s T-dimension is exactly 1/16″ less than the 5×12 holder, that allowed me to use a piece of 1/16 garolite for the bottom of the adapter. The adapter has a slot for the 4×10 riblock to fit into, and a riblock of its own to fit into the original back’s riblock slot…
I do have an obvious issue with pulling the darkslide when only one of the slides is reversed and the pulls are then aligned, making it difficult to grab the pull that’s tight to the back. I might have to redesign the pulls a little so they will always offset each other, regardless of orientation, but that is more difficult than it sounds. For now just using a spring clip to extend the pull.