When drilling deep holes (3 or more drill bit diameters deep) use lubricants (not water) to dissipate heat from the tip. Always use a lubricant while drilling aluminum. Drill a short distance and then back the drill bit out of the hole before progressing. This will help remove loosened chips from the flute and introduce more lubricant into the hole. Recommended cutting speeds: 2,500 RPM for smaller bits up to 1/8" and 600 RPM for larger bits up to 1/2" Use a sliding scale to decrease the speed for larger drill bits. Faster speeds can be used when drilling wood, composites, plastics, etc.