I know its basic but its my first!
The bottom metal washer can be removed or kept, up to you.
I thought id buy aluminium ones but there aren't any for M3 which will fit the spring inside.
PLEASE NOTE: If importing In Simplify3D, when asked to auto-scale to millimeter format chose NO.
PLEASE NOTE: For some will be obvious (for me it wasn't at the start..) When fitting the spacer, unscrew 2 of the thumb wheels on one side at the same time and you wont need to unscrew the m3 nuts, jut lift the bed side, place the 2 spacers below the spring, put screw trough.