Suitable for alloyed and non alloyed steel up to a tensile strength of 900 nmm cast steel cast ironsintered iron malleable cast ironnon ferrous matels and hard plastics pecison ground hhs g drill bits enables up to 40 faster drilling rate and up to 50 lower feed pressure than standard ground hss drill bitswith chisel edge self centering split point drill tip means there is no need to pre punch or pilot drill up to 10mm diameter the hss g drill bits are for the toughest jobs d 10mm l1 12mm