hi guys,
the last days i am trying to understand why i have bad surface when miling 7075 aluminium.
i am new without experience in these machines and i am searching to find the cause of all this.i measure my spindle runout at the er25 collet body and there is a 0.01mm runout per revolution.if i remove the er 25 holder and measure it at the spindle inself there is a runout of 0.006 mm .

my question is if this is normal and causes any kind of problems. as the endmil rotates i hear the sound changes in every recolution .
is this amount of runout normal?

my machine:
optimum bf20 vario
mt2 drawbar 10mm

no cooling
aluminium 7075

i have this machine not long time and one time i jamed the cuter so badly that the whole head rotated a bit and i forced to realighn the head.is it posible to bent the spindle and now have this runnout?

thanks