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This paper presents the results of drilling tests on cast iron and steel. Drills ranging in diameter from 1/2 to 1-1/2 in. of the standard twist-drill type were used. The drills were considered sharp in all tests. A coolant consisting of one part of soluble oil and 16 parts of water was used in all tests. The materials cut consisted of one regular machining cast iron and one cast iron made up of 20 per cent charcoal pig iron, together with 17 steels of a wide variety of chemical analyses, which were selected to cover the steels commonly used in modern manufacture. Data as to drilling torque, thrust, computed horsepower at the drill point, and net horsepower supplied to the machine as measured on a recording wattmeter are given under two headings: commercial tests and special tests. All commercial tests were run at a peripheral speed of the drill of approximately 60 ft. per min. The feed for each drill size was as near to those given in the usual commercial-drilling table as the change gears available would permit. They were as follows: 0.009 in. per rev. feed for the 1/2-in. diameter drill, 0.011 in. for the 5/8-in. drill, 0.012 in. for the 3/4-in. drill, 0.013 in. for the 1-in. drill and 0.015 in. for the 1-1/4- and 1-1/2-in. diameter drills. Special tests were run on various cast irons and steels so that the influence of the speed, feed, and drill diameter could be determined, in order that the results of the commercial-drilling tests could be extended to cover any other conditions of drilling for each material. It was found from these special tests that the thrust for both cast iron and steel increased in direct proportion to the drill diameter d; that the torque increased in proportion to d2 for cast iron and d1.8 for steel. The thrust increased with an increase in feed f, but at a rate as slow as f0.6 for both cast iron and steel. The torque increased as f0.6 for cast iron, but f0.78 for steel. It was found that the torque and thrust remained practically constant over the whole range of speeds covered from 74 to 441 r.p.m. for each drill size and feed. An attempt is made to correlate the hardness values of the materials determined by the Brinell, Rockwell, scleroscope, and Herbert pendulum hardness testers, with the results obtained from the drilling tests. It is concluded that no satisfactory relation exists between these properties.

Committee of the ASME Materials Processing Field: J. L. Wennberg, Therm, Inc., Chairman; B. F. von Turkovich, University of Illinois, Metal Cutting Analysis; J. R. Roubik, Kearney & Trecker Corp., Metal Cutting Practice; F. W. Boulger, Battelle Memorial Institute, Plastic Working of Metals; D. A. Farmer, Carnegie Institute of Technology, Grinding; P. A. Smith, Massachusetts Institute of Technology, Metalworking Fluids. The purpose of this review is to appraise the important contributions to the knowledge of material processing appearing in the published literature and to present a digest of this new knowledge through the Society as a contribution to the improvement of materials processing practices throughout industry.

The cutting action of a twist drill is very complex. This paper describes an investigation of this complex phenomenon through use of a quick-stop technique to freeze the action. The formation of chips, both along the cutting edges and under the chisel edge, is considered. Chip-flow angles, measured experimentally, are related to effective rake angle along the cutting edges, using a new derivation of the normal rake angle for a twist drill. The effects of point angle, drill design, and workpiece material are considered. The split (crankshaft) point for heavy web drills is investigated and its operation described.

By members of the Literature Review Committee of the ASME Metal Processing Research Activity: J. L. Wennberg, General Electric Company, Chairman; B. F. von Turkovich, University of Illinois, Metal Cutting Analysis; J. R. Roubik, Kearney & Trecker Corp., Metal Cutting Practice; F. W. Boulger, Battelle Memorial Institute of Technology, Plastic Working of Metals; R. S. Hahn, the Heald Machine Co., Grinding; P. A. Smith, Massachusetts Institute of Technology, Metalworking Fluids. The purpose of this review is to appraise the important contributions to the knowledge of material processing appearing in the published literature and to present a digest of this new knowledge through the Society as a contribution to the improvement of material processing practices throughout industry.

The influence of tap-drill size (minor diameter) upon the strength of threaded assemblies has been the subject of much speculation, analysis, and testing, but the results presented generally have been inconclusive or have not covered all of the many possible types of thread failure. This paper reports the results of a series of correlative tests and supporting analysis performed in an attempt to solve this problem. Failures can be of three types: Breakage of the external-thread member; stripping of the external thread; or stripping of the internal thread. The effect of drilled-hole oversize is examined and is found to be a significant variable in some cases. Formulas are developed which extend the experimental data to permit analysis of most practical thread-element combinations. For assemblies of usual proportions and materials, it is found that 60 per cent thread height is adequate.

The problem of computing the torque and thrust developed on a drill is approached from dimensional reasoning and the rules of cutting-force development in two-dimensional cutting. The drill quantity equivalent to the feed in ordinary machining is found to be the product of feed and diameter. General equations are derived for drill torque and thrust and found to be in good agreement with experimental data obtained by use of a drill dynamometer. The web thickness of the drill is found to influence thrust and torque significantly, but the influence of helix angle is found to be relatively unimportant.

This paper gives the results of a series of drilling tests on nine different metals using eleven different cutting fluids. Modern twist drills having 30-deg helices, ranging from ½ in. to 1½ in. in diameter, were used. The materials consisted of a cast aluminum alloy, free-cutting brass, cast iron, malleable cast iron, S.A.E. 1020 steel, S.A.E. 1035 steel, carbon tool steel, S.A.E. 3150 steel, and S.A.E. 1112 steel. The eleven cutting fluids consisted of dry cutting, borax water, two soluble oils, lard oil, two straight mineral oils, two compounded oils, and two sulphurized oils. For each material a formula for torque and thrust was developed as a function of variable diameter and variable feed. Constants for these formulas for dry cutting and each of the eleven cutting fluids are determined. The influence of the different cutting fluids on each metal is shown. With the net output power for drilling dry expressed as 100 per cent, the savings made are as follows: 33.3 per cent for S.A.E. 1020 steel when using a sulphurized oil 31.7 per cent for aluminum alloy when using a 90 per cent mineral-10 per cent lard oil 26.0 per cent for S.A.E. 1035 steel when using a sulphurized lard-mineral oil 23.0 per cent for S.A.E. 3150 steel when using a sulphurized mineral oil 21.0 per cent for carbon tool steel when using sulphurized mineral oil 17.2 per cent for cast iron when using a mineral oil containing 5 per cent oleic acid 10.5 per cent for malleable cast iron when using any kind of an oil, such as lard, mineral, compounded, or sulphurized 6.8 per cent for S.A.E. 1112 steel when using a sulphurized lard-mineral oil. No appreciable difference is made whether free-cutting brass is cut dry or with any kind of a cutting fluid. In the development of the formulas for torque and thrust, it was found that the same results of the exponents for drill diameter and feed would be obtained regardless of the diameter of the drill used in the variable feed tests and regardless of the feed used in the variable drill diameter tests. The values of these exponents are not influenced by the type of cutting fluid used. The torque and thrust lines as a function of feed or diameter as the variable are merely displaced vertically, if affected at all. The constants of the torque and thrust formulas, however, indicate the cutting characteristics of the cutting fluids. The torque and thrust formulas for all kinds of steels as covered in the paper are found to be identical except for different values of the constant. Other metals, however, produce formulas apparently characteristic of that metal. In other words, different formulas as summarized in Table 4 are developed for the aluminum alloy, the free-cutting brass, cast iron, malleable iron, and steel.

This paper presents the results of a series of experiments to determine the influence of eleven different cutting fluids on the power required to plane and drill an annealed S.A.E. 3150 steel. This investigation was conducted as a project of the Subcommittee on Cutting Fluids of the A.S.M.E. Special Research Committee on the Cutting of Metals, by the Department of Engineering Research of the University of Michigan, with funds provided by Engineering Foundation. The object was to secure definite performance data for certain limited conditions as a preliminary step to a comprehensive study of cutting fluids. The force required to cut metal by planing for a single tool shape was determined for a variety of feeds and depths of cut. A formula for the planing force is developed as a function of the cutting fluid, the depth of cut, and the feed as P = CD0.95f0.79. The torque, thrust, and power required to drill the S.A.E. 3150 steel are determined for a variety of drill diameters and feeds for each of the eleven cutting fluids. Formulas for each of these factors are developed as a function of the cutting fluid, the feed, and the drill diameter. Torque T = Cf 0.78 d 1.8 thrust B = Kf 0.87 ( d 5 + w d ) 2.12 . The results show clearly the relative advantages from a power standpoint of the various oils studied, and the constants C and K provide for the influence of the cutting fluid used. All data are presented graphically. An attempt is made to correlate various physical and chemical properties of the cutting fluids with the results of their cutting performance. It appears that cooling is the primary requisite of a cutting fluid rather than lubrication.