'Bytes' are something digital...i.e. a design concept on a computer, CAD file, etc. 'Bolts' are something real, material, exist in the real world...literally the metal connector pieces that hold the assembly together. 'Bytes to bolts' is then an allusion to the design and manufacturing process. If this is all done in one place, then they may be pointing to the fact that everything is done under one roof from design concept to assembly.