X and Y axis not 90 degrees

[dkerr]

I'm many hours into a confusing problem. On my 100W china laser, the X-axis does not cut at a 90 degree to the Y-axis. My gantry is true and square. When I move the head on the Y-axis front to back it stays straight (measuring from the gantry or wall to the laser head). When I move my X left to right, it measures a half-inch different for the left to right. In other words, from the front gantry rail to the X beam, it can be 5 inches from rail to beam, and on the other side, it will be 5.5 inches. I don't see any adjustments? When I tied to shim the rail end where it attaches to the mirror and guide assembly, it binds in the Y rails. It does a great job unless I need a square cut or a perfect circle, not other things you can't notice it's off.

The two pictures show what I was explaining, these are two left and right measurements from the true and straight gantry, to the x-axis beam.
The 3rd pic shows an L square up against the X axis beam showing how out of square it is.

Any help is greatly appreciated.
Thanks
Don

[peteeng]

No photos Don? Peter

[dkerr]

I tried to upload the photos, not sure if they came through, I uploaded them to this reply, hopefully you can see them.
Don

[dkerr]

not sure why photos aren't showing, I see them on my post - when I view the site not logged in, they are not there.

Technology is not working in my favor this week.....

I will try to get this figured out.
Don

[ZASto]

How did you check squareness of your gantry?

Did you made test firing at the 4 extreme corners of gantry travel and measure diagonals?
In the attached picture you can see the representation of gantry which is out of square, (over exaggerated), with Y "length" correct (~60 units)