Tool gets to the corner and the extra side force rotates/moves the tool to a smaller diameter, then the load increases, then it digs in more then it all turns to cr4p in the blink of an eye! WTF?
It happened to me the other day. Tool holder was not tightened adequately.
When it happens, sometimes takes a bit of detective work, if any evidence is left.
1000 RPM is OK. The more the merrier, with a spray of WD40.
Super X3. 3600rpm. Sheridan 6"x24" Lathe + more. Three ways to fix things: The right way, the other way, and maybe your way, which is possibly a faster wrong way.