Thanks, I'll give those things a try and post the results

Is there any possibility the cutter is being pushed into the collet?
Hood

OK, After taking a closer look at everything, here is what I did. I took apart the ball screw assembly for the z-axis and redid the upper bearing(felt like it was binding). Ground a flat on the ball screw shaft and
put another set screw in the coupling. I have a Lovejoy coupling now, but I'm going to install a more robust coupling just to be sure I'm not getting any slippage.
I also ran a test with a higher quality router bit and that also helped. Maybe I'm loosing some steps with too much force on a lower quality bit.
Before doing all the mechanical changes I took your advise and changed the Mach settings, and that did help but I think most of the issues are mechanical.
I also come to find out the table is not parallel with the gantry so I'm loosing about .03" as it traverses the y-axis.
The whole purpose for this part is new uprights for the gantry and new ballscrews on the x-axis. It looks like now I can make these parts before disassembling the whole machine to rework it....
Thanks to everyone for your help..
Art