Ruko 106 303 12 piece universal bi metal hole saw set ruko 106303 the ruko hss bi metal hole saws in this 12 piece set have varied tooth spacing and are suitable for unalloyed steel up to 700 n mm sup2 strength non ferrous and light metals plastics plasterboard and light building boards fibreboard plywood and wood they are particularly suitable for use with hand drills pillar drills and lathes ruko 106303 universal bi metal hole saw set 12pc