Bosch 2607019578 18 piece toughbox metal drill bit set hss g din 338 135suitable for alloyed and non alloyed steel up to a tensile strength of 900 nmm cast steel cast iron sintered iron malleable cast iron non ferrous metals hard plastics precision ground hss g drill bit enables up to 40 faster drilling rate and up to 50 lower feed pressure than standard ground hss drill bits with a chisel edge key features self centring split point drill tip there is no need to pre punch or pilot drill up to