There is no particularly special technology needed to make a chainsaw. It's really just plastic and metal parts screwed together with old-fashioned nuts and bolts.

Assembly tools for screws and nuts - double - headed open - ended wrenches, double - headed ring wrenches and combination wrenches - maximum widths of heads.

Assembly tool for screws and nuts - open - end double - head engineers wrenches, double - head box wrenches and combination wrenches - maximum outside dimensions of heads.