So yesterday everything was working great, today, not so much… I’m getting offsets on both the X and Y axis. Computer is running windows 10, but it was yesterday also when things seemed to be working ok. The belts are both good and tight, same as they have been for the last month, no slipping appears to be happening. When I end the job the machine is not homing to the correct location, it is offset just like the cuts. I tried adjusting the g-shield pots as well today but everything seems OK there too. When I move the machine with the easel homing controls I can repeatedly move it on the X and Y axis 8" at a time repeatedly without any issues. My design has a lot of circular cuts where both axis are being operated at the same time. I have the larger nema 23 stepper motors and am wondering if my power supply is to blame? I"m not sure what else I can check, any suggestions?
What kind of spindle you have.
Is it only missing steps when under load (ie cutting)?
If so then it may be the bit, feedrate, doc or material you are trying to cut is putting to much force on the spindle.
I have the 300w spindle, happens when under no cutting load as well.
That is not good 
Try leaving the XC on with the spindle running but no cut program. Watch the gee lights on the GShiled. If they are flickering that may mean that the spindle is causing interference in the stepper drivers.
If the stepper motors are actual moving / shifting they it definitely is causing interface and needs to be replaced.
Contact inventables about replacing it or getting credit toward a mount for a different motor.
Ahhh, thanks for the tip. Leaving the XC powered on but spindle off the Gshield led’s didn’t change. However turning the spindle on did cause them to start toggling intermittently. I guess the spindle is bad 
I really appreciate the help, at least now I know why it was acting up!
I just reran the job twice, both under no load.
- First with the spindle rotating (offsets occurred)
- Second with the spindle off (worked perfectly).
Spindle is definitely causing my issue.
Ugh, well at least you know what the problem is.
As I understand it you may be able to fit a Dremel into the standard mount so you can get carving while you wait for a replacement spindle or mount.
FYI: If you decide to upgrade your spindle and go with the Dewalt 611 you will need a dust shoe. I also highly recommend doing a stiffing mod as well.
Welcome to the Club. If you’re willing to buy Dewalt 611, inventables can send you a mount as a replacement. It is up to you. You have multiple choices.
I heard the problems have been fixed, but when are they going to throw in the towel on this 300W spindle? This one issue has to be killing them on returns, refunds, etc. It would make more sense to resell the 611 at a slight discount from retail, w/ the proper mount.
Jeremy, Try adjusting your axis pots all the way to max and then backing off about 1/8 turn. This is what I had to do to get mine to stop overwriting letters and achieve even spacing. Look at this link,(Using grblShield · synthetos/grblShield Wiki · GitHub) maybe it will help you as it did me.
i have shift job, when i want to carve circle , the bit
stick in the material and changing the bath ,it seems that z axis changing the path and go down , i change the bit, change the material,set the belt,check all the connection, what are your idea about this issue .