PRECSISON TWIST DRILL 342SDT drills have a 1/2 inch parallel tri-flat shank so even large diameter drills can be held in conventional hand held power tools. They come with a dual steam oxide finish to prevent workpiece material from sticking to the cutting surfaces of the tool, so ensuring clean and accurate holes. They are manufactured from High Speed Steel and are suitable for drilling many materials including steels, stainless steel and aluminum, and have 118 degree conventional points which gives a strong point, easy to regrind, so the drills can be re-sharpened many times over. 342SDT reduced, tri-flat shank drills are very versatile and can be used in the many different machine and hand held applications of the maintenance and repair professional.