# Y rails off slightly

**URL:** <https://forum.onefinitycnc.com/t/y-rails-off-slightly/8370>\
**Category:** Original/PRO Series (Buildbotics) (Gen 1)\
**Created:** [October 18, 2021, 9:29pm UTC](https://forum.onefinitycnc.com/t/y-rails-off-slightly/8370 "2021-10-18T21:29:53Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![349iq2345](https://avatars.discourse-cdn.com/v4/letter/3/bb73d2/32.png) [@349iq2345](https://forum.onefinitycnc.com/u/349iq2345)\
**Post date:** [October 18, 2021, 9:37pm UTC](https://forum.onefinitycnc.com/t/y-rails-off-slightly/8370/2 "2021-10-18T21:37:43Z")

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Hey Van,

is your X/Y assembly rectangular (“_squared_”)?

This has been [discussed here the other day](https://forum.onefinitycnc.com/t/is-your-router-frame-a-parallelogram-mine-was/6086). The simpliest way to check this is whether the diagonals are identical. A rectangle, i.e. which has right angles, has identical diagonals. If the diagonals differ, then it is no rectangle, but a parallelogram, i.e. your angles are not right angles, which means your machine is “_not squared_”.

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