I learned years ago, that a reasonable replace for a universal when you can't find one, is model air plane fuel line. It comes in various grades and I use the more flexible. You just slip it on the shafts and you are ready to go. The flexible tubing works like a universal. I have done about 4-5 old steamers this way when replacing motors. I did not want to try to solder the old universals on the motor shaft for fear of damaging the motor from the heat. This is something you can use when the shaft sizes are not quite straight aligned with each other, or when you are dealing with different shaft sizes on the motor and gearbox. I haven't bought any for years. I bought a foot or so for a few bucks the last time I bought some.