I have make a little test with 4 dots aligned with A tower, B and C tower. Distance W and S are the same in the stl but not in the print. I have tried diferent values of diagonal root but S always is smaller than W, and all S are equal (more or less 38.20mm) and all W are equal (more or less 40.80). I expect that W and S will be 40mm. How can fix this problem?

[![enter image description here][1]][1]

**Update:**

Here is the stl I use: https://www.dropbox.com/s/2vwjbo387cmk5qa/DeltaCalibration%20v15.stl?dl=0

  [1]: https://i.sstatic.net/hkUAj.png