COOLANT AND CUTTING FLUID

There may be instances where drilling is enhanced by the introduction of a suitable coolant/cutting fluid, while other materials such as Nimonic and Manganese Alloys should be cut dry.  In order to use a safe drill bit with maximum pressure, a large supply of fluid is needed to keep the tip temperature to an acceptable level.  Usually the resultant spillage and splashing is not tolerable in anything but a workshop environment, so you must drill dry.  There are a few gel and spray fluids available and users may find some improvement by using one of these.  The danger here is that the use of small quantities can sometimes cause rapid variations of temperature as the tip heats, and localized partial quenching occurs.  This can result in thermal stress cracks developing in the tip and rapid deterioration of the drill bit.  Also, some gels or sprays are prone to make unpleasant smoke.