Absolutely agree that when the steppers are locks machine will not go out of square as you can’t move either side of the tube.
The problem of squareness is probably a result of my working method.
I clamp a blank somewhere on the working area reset the axis position to 0 and position the “head” dragging it by hand. When the router bit is in position execute a “print from SD”.
When I drag the “head” to position I need the motors to be unlocked and probably not always I drag it evenly from both sides.
So now after I square the axis i never drag it by hand just move it using the controller and when it is in place reset origin (set all axis to 0).
If in any way I could “stiffen up” the axis cross it would make things eaisier.
This is maybe what this fella wanted to achieve
Thanks for the link you sent. Yes this make the squaring process easier and I think this guy faced similar problems to mine 😛