HSS-E Cobalt = hardness 65 HRC, to machine steels up to 1000 N/mm², cast iron up to 180 HB, copper, brass, bronze, aluminium.
Center drills for threaded spindles are designed to do the following in a single operation :
make the preliminary tap hole
make the tap entrance
do the centering radius
Main use :
To center or to bore the shafts of electric motors, pumps, speed-reducing gear.
