Use a template for drilling holes in octet truss, to ensure that all holes are the same and identically located. Print on paper first,then trace or laminate onto cardboard and punch hole centers per template guides. Provided octet truss welding work is standard, dimensional tolerance of ±1 mm is achievable. Square face bolted connection is 20×20 cm, with holes of sufficient tolerance for no. 17 bolts. Drill templates are here in PDF: octet truss face joint, octet truss face joint -alt (print to A4 size sheet).