Speeds/Feeds for Deep Hole Drilling

Speeds and Feeds for Deep Hole Drilling:

 

Holes which must be drilled three or more diameters deep fall into the "Deep Hole" drilling class and some adjustment of speeds and feeds is necessary.

 

The deeper the hole, the greated the tendency for chips to pack and clog the flutes of the drill.  This increases the amount of heat generated and prevents coolant from reaching the drill points.  Heat buildup will eventually result in premature failure of the drill.

 

Step drilling, that is, drilling a short distance and then retracting the drill, will often reduce the chip packing.  The deeper the hole the more often the drill must be retracted.

 

A reduction in speed and feed to reduce the amount of heat generated is generally required in most deep-hole applications where coolant cannot be effectively applied.  For Speed and Feed Reduction Percentages for Deep Hole Drilling, please see the following chart.

 

Hole Depth	Reduce Speed by:	Reduce Feed by:
3 x drill diameter	10%	10%
4 x drill diameter	20%	10%
5 x drill diameter	30%	20%
6 x drill diameter	40%	20%