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).
Spacecraft . octet truss face joint
The two outermost square faces of semi-octet trusses join in a bolted connection to form an octehedron. Holes for bolts should be pre-drilled for easy assembly, using this drill template or similar.