There are blades available for these........ either make your own or, if I remember correctly, Kunz in Germany used to offer a direct replacement. Notwithstanding the horrendous import costs of stuff from Europe nowadays.
From my own plane's measurements, and amongst other likely spares, the Lie-Nielsen blade is too thick for the Stanley throat, though the Veritas equivalent will work, even if it's a slightly different shape.
To do your own, you need plate that is no more than 3/32 thick. There is no tension screw, so file it dead straight across (take off the corner arises) and turn your burr onto that. Some folk file at 45 degrees and just burr one side, but I do it dead square and burr both edges so that it can be turned when blunt. It's a matter of choice.
Good luck.