"For brass or other soft metals there may be used with advantage a twist drill as shown. The cutting edges of the drill are ground straight and in line with the body of the drill for a distance of 0.03 to 0.06 in. = 0.8 to 1.6 mm. This prevents the breaking of the drill when it goes through the work—piece." —Grimshaw, 1902

Twist Drills for Brass

"For brass or other soft metals there may be used with advantage a twist drill as shown. The cutting…