Well, I just had a go - I only had a 4 flute 2mm dia end mill to hand - I went with 4 cuts @ 0.2mm cut depth per perimeter run, squirting a bit of wd40 (it was all I had!) once in a while - the end result was very reasonable (though a degree of deburring will be in order. I couldn't bring myself to use the higher feed rates, so went with 150mm per minute.

That said, I could telll that my machine/spindle wasn't particularly happy (I understand it better than my wife now) - it's used to acrylic! But at the end of the day, there was no real drama (unlike with my wife). Material clamping is an issue though, ie that last bit where the part is fully cut out from the material - it's tin helmet time. Not pleasant.

Nice to know though - ie that for the odd thin steel widget, my humble DIY machine will grudgingly comply.