Insert an LM8UU linear bearing into the x_end_idler until it hits the internal stop.

The next LM8UU linear bearing will have to be inserted so that the rows of ball bearings are at 45° to the rows in the other bearing.

Insert that LM8UU linear bearing into the x_end_idler until it hits the internal stop.

Verify that the rows of balls are rotated at an angle of 45° from each other (as shown in the photograph).