Drill Bits

Speed and feeds for deep-hole drilling

 

Holes which must be drilled three diameters deep or more fall into the "deep-hole"drilling class,and some adjustment of feeds and speeds is necessary.The deeper the hole,the greater the tendency there is for chips to pack and clog the flutes of dirll bits.This increases the amount of heat generated and prevents the coolant from conducting the heat away form the point .A build-up of heat at the point will eventually result in premature failure.

  Step drilling,also called "peck" drilling ,is the practice of drilling a short distance ,then withdrawing the drill bits.This often reduces chip packing .The deeper the hole ,the more frequent the dirll must be retracted to be effective.Generally,a reduction in speed and feed to reduce the amount of heat generated is required in most deep -hole applica-tions,wherw coolant cannot be effectively applied.