I’ll play. Your zip ties are too long. One end should be pretty much snugged up to the corner piece. The other end shouldn’t be much longer than a half inch, and the sides should be flat. If the tie is still roundish after tightening, it’s not tight enough, it will spring. Cut the tie holding the power cable on the tower. Those tubes are a lever, and any movement on the top will cause the opposite movement on the end mill side.[attachment file=72504]
As for the router…
Sorry, couldn’t resist… It’s little too big I think. If it’s glued, how do you adjust perpendicularity? If it’s not 90 to the work surface it will cause issues the deeper you cut. If there’s an angle, your first 2mm pass will be alright, but the next 2mm pass might be cutting 2.5 or even 3 mm. The next will be worse. Eventually the bit will start to pull the router around. Also straight bits aren’t the best for cnc.
Not trying to slam your build, it’s pretty cool, just throwing my .4¢(inflation) out there to try to avoid some frustration.