The drill is the most efficient tool used by machinists, for in no other tool is the cutting surface as large in proportion to the cross sectional area of the body or part that is its real support. Drills have shared evolutionary developments from carbon steels to high speed steels and from flat to twist drills. Many investigations have been made on the twist drills, but due to the majority of their work being based on the size of drills from 1/2 to 1-1/2 inches or larger, there is a dearth of published data on the general problem of drills of smaller sizes, such as the diameter of drills smaller than 1/2 inch in diameter. Therefore, the object of this investigation is to determine the torque characteristics of certain commercial small drills and to evaluate the effect of various factors on the torque --Introduction, page 1
