Hi all!

I have a new 770MX, and I keep stalling the spindle. I'm not sure if this is an issue with my speeds and feeds (I'm using GWizard, but I'm very new to it), or an issue with the machine itself. I've had the spindle stall 6 times now, with different operations, and both 3/8" and 1/4" diameter tools. After the first couple of stalls, I thought the drive belt might have been too loose, so I tightened it a bit, but I'm still having the same issue (the belt is in high and it is also set to high in pathpilot!). Just before the spindle stalls, I get a readout saying that the spindle encoder RPM feedback is abnormally low, and to run an admin encoder test, which it passes easily every time. Here are the details for the most recent operation it was doing when it stalled while working in 6061 Alu:

3/8" YG-1 end mill (36584)
0.2145 DOC
0.12 WOC (GWizard told me to set this to 0.3363, but I was trying to be conservative since I kept stalling the spindle)
7197 RPM
71.504 IPM
Flood Coolant
Stalled on 3rd Pass

I got the above data after entering the SFC (785) and IPT (0.0041) that I calculated from the recommended speeds and feeds on YG-1's website (8000 RPM @ 99 IPM). Since I was worried I had calculated this wrong, I cleared these fields and let GWizard calculate these values for me, as I read this was a safe way of doing things, but the below data from GWizard also stalled the spindle.


3/8" YG-1 end mill (36584)
0.2145 DOC
0.1775 WOC
10000 RPM
67.922 IPM
Flood Coolant
Stalled 1" into the first pass

What am I doing wrong? Thanks in advance!