Using a cm tape rule, the X-axis rails are 28 1/2 cm long, (285 mm).
The possible error in measurement is a total of three millimeters.
I suggest cutting 29 cm, to ensure you have the X-axis length you need, and cut it down later, if you need to.
The SD2 can hang the extra length outside the outside frame: Take a look at the area.
But -
you might want to check the far X side X-axis holding [fixture/mounting point].
- The X-axis rods are ~ flush with the outside, on my rig.
So, the exact distance may be different on your machine.
I cannot see how to dis assemble the two mounting points for the X-axis.
Looking at the works, on both ends of the Y-axis,
-> how much can you do without dis assembly?
James.