Hello,

I'm having a little trouble setting correct settings (I'm new in this) for mill aluminium 6063-T5 on a RTM-80-2.2 (https://www.aliexpress.com/item/32880152613.html) spindle. Calculator gives crazy feeds and i'm not sure to trust them.
The only sucessfull mill was using a 3.175mm 2 flute at 5000RPM and 150mm/m feed, then i boost to 200 and even 250mm/m without break the tool.
Now i want use a HSS 8mm 2F bit for a big pocket and i like to ask first before use it and ruin something. For example calculator gives 6310RPM at 1413.52mm/m for a DOC of 1mm and 8mm pocket.
After reading about these spindles i notice they are not good at low RPMs, some websites say 6000, people says 4000/6000/8000 and i ask the seller which told 9000 as minimum. Also i ask for power curve but none have such data... So with that high variance of RPMs min, what should i take? The seller recommendation?
Also does my previous cut at 5000RPM can wear spindle or damage it if i continue use such RPMs?

Heres a picture of my first sucessfull mill on Alu:



PS: My machine is a 9060 homemade all made of steel and linear guides