Been tinkering with Carbide endmills VS HSS. Now I am not the best in figuring speeds and feeds, go with what is working at the time. Got schooled today, was told to quit wimping out and let er RUN. So I bumped my feeds to 40 IPM ( From the low 20's )in Aluminum, 2 flute HSS Endmill. Cuts fine. Swap out to a Carbide, 2 flute, and chatters like crazy. Both endmills are in a Endmill holder, no collet, RPM at 6k, feed the same, 40IPM.
What am I missing, or doing wrong most likely.
Thanks for your time,