Peterson System Pipe Stem Replacement

Darmon

Does anyone know of anywhere I could get a rough stem like what Vermont Freehand sells but for the Peterson System Pipes. I'm not looking to send the pipe into Peterson, I know they do repairs and stem replacements but I was looking for doing some of the work myself and just finding a rough blank.  I tried Vermont Freehand but I couldn't find one big enough for the 312 system pipe I have.