C20R18 sets contains 20 different sized R18 drill bits from N61 to N80. These drill bits can be used in many different applications and are suitable for both hand held and machine use. Manufactured from High Speed Steel, they are good for drilling many materials including stainless steel, aluminum and steels. They come with a conventional 118 degree point which gives strength and also makes it easy to re-grind the tool to be used again and again. For clean and accurate holes, R18 drills come with a bright finish to prevent workpiece material from sticking to the cutting surfaces of the tool.