Boring is a machining process in which internal diameters are generated in true relation to the centerline of the spindle by means of single-point cutting tools. This article provides a discussion on boring machines and boring tools and presents a comprehensive discussion on the various elements of boring. The elements are composition and hardness of workpiece metal, cutting fluid, speeds and feeds, and methods for piloting and supporting tools in boring applications. The article explains the role of workpiece size in selecting the equipment and processing procedure and the use of techniques to overcome difficulties presented by workpiece configuration. It describes the factors related to accuracy of boring and factors affecting them. The article also presents a discussion on close-tolerance boring and methods of controlling vibration and chatter. It concludes with a section presenting information on the use of boring equipment for machining operations other than boring.

Honing serves an important purpose of generating specified functional characteristics for surfaces besides removing stock and involves the correction of errors resulting from previous machining operations. This article discusses the process capabilities of honing in terms of bore size, bore shape, and stock removal. It illustrates the uses of air, ring, expanding, plug, and bar gages for automatic size control in power stroking of honing tools. The article provides a short description of various honing processes, such as external honing, gear tooth honing, plateau honing, flat honing, electrochemical honing, and hone forming. It also examines various process parameters in microhoning and concludes with information on the applications of microhoning.

This article describes various machining techniques of refractory metals, namely, niobium, molybdenum, tantalum, and tungsten. These include turning, boring, trepanning, reaming, milling, tapping, drilling, and sawing. Parameters for the machining of the refractory metals are also tabulated. In addition, the article provides information on cutting fluids and tools that are used in machining of the refractory metals as well as on the safety precautions to be followed in the machining process.

This article describes the selection of tool steels on the basis of specific product applications. It contains tables that list nominal speeds and feeds for the machining of various tool steels. The machining processes include turning, boring, broaching, drilling, reaming, tapping, milling, and sawing. The article explains the machining of the following tool steels: water hardening; types A, D and O cold-work; hot work; high speed, low-alloy special-purpose; and low-carbon mold. It details the machining of tool steel gears. The article also discusses the grinding of tool steels based on steel classification and the effects of steel composition and hardness on grindability. It reviews the types of grinding, namely, surface grinding, cylindrical grinding, centerless grinding, internal grinding, thread grinding, flute grinding, and low-stress grinding. Grinding of types-A, D, F, L, O, P, S and W steels, hot-work steels, and high speed steels, is also detailed.

Powder metallurgy is a near-net shape process capable of producing complex parts with little or no need for secondary operations such as machining, joining, or assembly. However, the inability to produce certain geometrical figures such as transverse holes, undercuts, and threads frequently necessitates some machining, particularly drilling. This article provides a discussion on the measures that can optimize the machining of P/M materials. It reviews the factors influencing machinability of P/M components, including workpiece and tool material properties, cutting conditions, machine and cutting tool parameters as well as some P/M material and production process parameters. These parameters discussed include the particle size, part geometry, porosity, compaction and sintering methods. In addition, the article presents guidelines for the various machining processes, namely, turning and boring, milling, drilling, grinding, reaming, burnishing, tapping, and honing and lapping.

This article discusses the factors influencing cast iron machining and selection of cutting fluid and cutting tool materials. It presents a comparison of machinability of different types of cast iron, namely, gray cast iron, ductile cast iron, and malleable cast iron. In addition, the article provides an overview of different methods used in the machining of cast iron, namely, turning, boring, broaching, planing and shaping, drilling, reaming, counterboring and spotfacing, tapping, milling, grinding, and honing and lapping. Nominal speeds and feeds for the machining of cast iron with single-point and box tools, ceramic tools, high-speed steel, and carbide tools are also tabulated.

This article begins with a discussion on the classification of aluminum alloys and the selection of alloy and temper based on machinability. It provides an overview of cutting force and power, tool design and material, and general machining conditions. In addition, the article discusses distortion and dimensional variation and machining problems during the machining of high-silicon aluminum alloy. It also provides information on tool design and material, speed and feed, and the cutting fluid used for various machining processes, namely, turning, boring, planing and shaping, broaching, reaming, tapping, milling, sawing, grinding, honing, and lapping. The article concludes with a discussion on drilling operations in automatic bar and chucking machines and drill presses.

Magnesium is machined in low-volume production on small, manually operated machine tools and on large, specially built, completely automated transfer machines operating at high production rates. This article focuses on the factors that affect the machining of magnesium. It discusses chip formation and distortion due to thermal expansion, cold work, and clamping and provides information on magnesium-matrix composites. The article describes materials, design, and sharpness as factors for selection of tool for machining magnesium. It illustrates turning and boring, planing and shaping, broaching, drilling, reaming, counterboring, milling, sawing, and grinding operations performed on magnesium. Safety measures related to machining, handling of chips and fines, and fire extinguishing are also discussed.

This article discusses various machining techniques of zinc alloy die castings. These include turning, boring, drilling, reaming, tapping, die threading, milling, and sawing. In addition, the article describes the factors that influence machinability of the zinc alloy die castings.

Cemented carbides belong to a class of hard, wear-resistant, refractory materials in which the hard carbide particles are bound together, or cemented, by a soft and ductile metal binder. The performance of cemented carbide as a cutting tool lies between that of tool steel and cermets. Almost 50% of the total production of cemented carbides is used for nonmetal cutting applications. Their properties also make them appropriate materials for structural components, including plungers, boring bars, powder compacting dies and punches, high-pressure dies and punches, and pulverizing hammers. This article discusses the manufacture, microstructure, composition, classifications, and physical and mechanical properties of cemented carbides, as well as their machining and nonmachining applications. It examines the relationship between the workpiece material, cutting tool and operational parameters, and provides suggestions to simplify the choice of cutting tool for a given machining application. It also examines new tool geometries, tailored substrates, and the application of thin, hard coatings to cemented carbides by chemical vapor deposition and physical vapor deposition. It discusses the tool wear mechanisms and the methods available for holding the carbide tool. The article is limited to tungsten carbide cobalt-base materials.

This article focuses on friction, lubrication, and wear of internal combustion engine parts, improvements in which provide important gains in energy efficiency, performance, and longevity of the internal combustion (IC) engine systems. It discusses the types, component materials, and Friction and Wear Control of IC engine. The article explains the process of friction reduction by surface textures or coatings. It provides information on surface hardening of iron and steel, which is commonly employed for engine and powertrain components such as crankshafts, cams, and cylinder liners. The article also discusses advanced surface engineering technologies, such as diamondlike carbon coatings and surface texture technology. Information on thermal-spray methods that have led to improvements in engine components is also provided. The article describes IC engine-components wear, namely, piston assembly wear, valvetrain wear, cylinder-bore wear, and engine bearing wear. It concludes with information on inlet valve and seat wear of IC engine.

Roller burnishing is a method of working a metal surface to improve its finish and dimensional accuracy and can provide some degree of work hardening. This article discusses the workpiece requirements used for roller burnishing. It illustrates the types of roller burnishing tools, such as internal tool, external tool, and tools for the roller burnishing of tapered holes and circular flat surfaces. The article contains a table that lists typical inside and outside diameter speed and feed rates for roller burnishing tools. It exemplifies typical lubrication techniques and the conditions used in the roller burnishing of magnesium alloy castings. The article reviews fillet rolling that is used to improve fatigue resistance of the materials. It concludes with a discussion on the process considerations for three basic types of bearingizing tools for the finishing of bores: bottoming, semi-bottoming, and through-hole.

This article describes the benefits that can be achieved by using thermal spray on particular engine parts of an automobile. These include improvement in fuel consumption, wear resistance and bonding, and reduction of oil consumption, exhaust heat loss, and cooling heat loss. Typical engine parts are cylinder blocks, cylinder bores, cast iron cylinder liners, piston rings, connecting rod bearings, turbochargers, engine valve lifters, exhaust system parts, and oxygen sensors. The article also describes the benefits of using thermal spray on transmission parts such as synchronizer rings and torque converters.

Trepanning is used in at least four distinct production applications: round disks, large shallow through holes, circular grooves, and deep holes. This article provides an overview of the first three applications. It describes the machines, tools, techniques, and cutting fluids used for deep-hole trepanning. The article contains a table that lists speeds and feeds for the deep-hole trepanning of various steels with high-speed tool steels and carbide tools.

Machining or material removal processes are secondary manufacturing operations that are used to achieve precise tolerances or to impart controlled surface finishes to a part. This article summarizes rules for designing parts to improve machined part quality and reduce machining costs in mass and batch production environments. It discusses the factors affecting the total cost of a machining operation, including raw material costs, labor costs, and equipment costs. The article describes three types of machining systems, namely, general-purpose machine tools, production machining systems, and computer numerically controlled (CNC) machining systems. It reviews general design-for-machining rules that are applicable to all parts, regardless of the type of equipment used to produce them. Special considerations for production machining systems and CNC machining systems are discussed. The article describes the structure and typical uses of computer-aided process planning and design-for-manufacturing programs.

This article provides information on radial friction welding, which adopts the principle of rotating and compressing a solid ring around two stationary pipe. The process evolution of this welding is illustrated. The article also examines the equipment used and operating steps. It also illustrates a prototype of radial friction-welding machine and concludes with a discussion on applications that would be suitable for radial friction welding.

This article summarizes the various kinds of gear wear, including fatigue, impact fracture, wear, and stress rupture, describes how gear life in service is estimated. It presents the rules concerning lubricants in designing gearing and analyzing failures of gears. The article presents the equations for determining surface durability and life of gears. It tabulates the situations and concepts of pitting failures in gears. The article analyzes some of the more common flaws that affect the life of gear teeth. It reviews the components in the design and structure of each gear and/or gear train that must be considered in conjunction with the teeth.

Gears can fail in many different ways, and except for an increase in noise level and vibration, there is often no indication of difficulty until total failure occurs. This article reviews the major types of gears and the basic principles of gear-tooth contact. It discusses the loading conditions and stresses that effect gear strength and durability. The article provides information on different gear materials, the common types and causes of gear failures, and the procedures employed to analyze them. Finally, it presents a chosen few examples to illustrate a systematic approach to the failure examination.

The ultrasonic machining (USM) process consists of two methods, namely, ultrasonic impact grinding and rotary USM. This article lists the major ultrasonic components that are similar to both rotary USM and ultrasonic impact grinding. It also provides schematic representations of the components used in rotary USM and ultrasonic impact grinding. The article describes the operations of the components of the rotary ultrasonic machine and ultrasonic impact grinding machine. It discusses the applications of the rotary ultrasonic machine: drilling, milling, and surface grinding. The article concludes with information on machining characteristics of ultrasonic impact grinding.

This article describes the secondary operations for cemented carbide parts, namely, diamond grinding, honing, electrical discharge machining, and brazing after sintering to achieve desired results, such as specified size, shape, edge condition, and surface finish.