Perhaps this is different when using Carbide’s drag bit but I’ve had my own since long before they were available. I’ve entered my own under “Engravers” in my custom bit catalog but when I select one for use the resulting dialog will not close unless I modify the speed to be non-zero.
This means I must consequently open the NC file in a text editor and, by hand, eliminate the spindle command. At best this seems tedious and unnecessary. At worst, I have ruined pieces when forgetting to do this.