If you are using the low cost spindle, it may be an EMC issue. I had strange moves in y-direction. Have a look at Chatter Issue - #13 by MichaelMayerhofer and scroll down to the bottom.
If you are using the low cost spindle, it may be an EMC issue. I had strange moves in y-direction. Have a look at Chatter Issue - #13 by MichaelMayerhofer and scroll down to the bottom.