Manufactured from High Speed cobalt (HSCo), R10CO NAS907 type J jobber drills are available in sizes from 1/64 inch to 11/16 inch and can be used for drilling hard materials including tool steel. The 135 degree split point is an aid to self-centering and reduces the amount of force needed to drill the hole, whilst the bronze oxide finish prevents workpiece material from sticking to the surfaces of the drill so you get clean, accurate holes. R10CO jobber drills have a heavy duty design, recommended for use in difficult materials and applications.