Hello all, newbie here just starting out with cnc.
I have had my 770 for a few months and today was cutting a L00 lathe chuck wrench from 1/4 1018 CR plate.

Using G Wizard I set up 3/8 4 flute carbide at 3100 RPM (300SFM), 0.080 DOC, full slot 0.375 WOC, 15 IPM, 0.0047 IPR.
Cut started ok then stalled spindle several inches into the cut, I lowered DOC to 0.06 and feed to 10 IPM and completed the job after re indexing XY ( apparently the servo drive belt had slipped).

Question is... G wizard claims 0.3 HP so I thought I was safe at these settings, yet I stalled the spindle.
After completing the cut I examined the cutter under 10x and sad to say this brand new end mill looks worse for the wear.

Is there something I am missing in my calcs?
Any help greatly appreciated.