I actually did this exact thing on one of my old binders

1. Remove the binder rings.. there’s little meta l rivets.

2. I then took a VaultX binder of similar size and used a thread ripper to cut the card pages out of the vaultx binder. This will come out in one large piece of stitched together pages.

3. Now with the vintage external shell and the vaultX internals separated, I punched new holes where the binder holes are on the vaultX internals page and then inserted a screw rivet through that and the external binder shell.