Coolant
Each Rotabroach Cutter is provided with a hole through the shank. This allows the flow of coolant through the center of the tool. A good flow of cutting fluid through the tool is important. It cools and lubricates the cutting edge, helps evacuate the chips, keeps the slug from expanding and helps eject the slug. A coolant system capable of delivering approximately 5 GPM at a minimum of 50 PSI is desired. Centrifugal pumps which may deliver a good flow at low pressure usually do not have the pressure capability to maintain the flow once the drill is engaged in the cut. They may deliver only a trickle in deeper holes when the coolant is needed most.
Many machines are available with through-the-spindle high pressure coolant. For other machines, spindle adapters with coolant inducers are available from Hougen.
