[Cory]

Broaching with a drill press, milll, etc, is a very bad idea.

While it may be acceptable for small keways, you can brinnell the spindle bearings, which basically means you indented the race of the bearing with one or more of the balls. This will ruin your tool.

Arbor presses are so cheap ($100-200) that it's not worth destroying a machine using it for something it wasn't intended for. Especially given how often an arbor press is used.