I'm trying to assemble Rework version (got it at Replikeo). In Connecting X and Z axes part, on step 3 it says "Insert two smooth Ø8x320 mm carefully on both Z Axis Top and slide them by half". Rods will not fit thro the opening no matter how hard I try (without cracking Z Axis tops). Is it wrong instructions or I need to enlarge holes with dril? Any other advise?