I have two 50mm axles in need of a new home. Don’t know the manufacture. One is marked with an “S” and is .070″ wall thickness. It’s been used about 3 times and is in excellent condition. The second is marked with an “M” and is .082 wall thickness. It has never been used.
Heat treatment/hardness are unknown. If anyone knows the manufacture or anything about these axles please post a reply.