Forging a Metal Shaping Machine

Hi!

You know those metal shaping machines used to cut grooves and straight lines? I think today they're called CNC Mills. I found a link to this manual for a Manual (non electric) Metal Shaping Machine: http://www.lathes.co.uk/perfecto/page2.html

I was wondering, before machines like this existed, there must have been methods for achieving the same results by hand. Can anyone elaborate on the tools and methods for doing so?

Thanks much in advance!