Hi cropwell
I am going to try pressing it first as the company I purchased the broach from said that it is very feasible to press it into mild steel as long as the hole is the correct size IE for a 11mm hexagon hole the hole needs to be 11.2mm I have a 7/16 bit ( 11.1250mm) but I also have a 11.5mm bit just in case .
Going to do it next week with a 30 ton press.
Will post success or failure.
Dell