What size clamping holes ?

[dudz]

I still need to work on my drilling methods. When I used the counterbore endmills it seemed to cut with ease. When I drilled the holes with 5mm and 6mm HSS bits, it screamed like a "B$*ch" . Im not sure if I had the feedrates etc correct. Sounded like the Bits were blunt to me. / plunge rate 0 / Cutfeedrate 800 / Peck 2mm / spindle speed (I tried 8000 - 15000 ) / Target depth -11mm / tool dia 4mm and 6mm / used cutting fluid and air.
Where do I put the input "400mm/min" for spiral down ?? can't find this in cambam for drilling (only for pockets and profiles), only cut feedrate in drilling .