I want to mill steel with this machine.

Maybe it just to bite the bullet if they can do what you want.

i only see VHM 6mm bit as a solution for the job
if you can clamp 8-12mm use Co8 7teeth that will do it even on plasma hole roughness

there are used VHM even TIAN on ebay less then 20Euros 5pcs that can be burned off

tecno wrote: Maybe it just to bite the bullet if they can do what you want.

Can't cause I am already buying a new ATC spindle. That is more important. I need to speed up my own things I produce.

So I also really want this table and having a router and a plasma CNC I really don't want to spend money on another company

Is this the type of endmill with inserts you guys were proposing to use to mill this?

Why not do this:
- use the router to spot the center of the holes
- manually make undersized holes
- finish them with a carbide 4mm endmill on the router (I would avise full depth cuts)
That way you won't have to mill hardened steel, won't put a lot of strain on the z axis drilling and if you take light passes with the end mill the machine won't suffer.
I'm sure that a 4mm end mill will snap off before putting too much strain to the machine

YES on the tool you showed
make shure you can insert CARBIDE bits
the standard may loose quick the edges on Plasma cut preholes
if you do a standard predrill they will work great