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Unformatted text preview: TC 9-524 Chapter 5 GRINDING MACHINES Grinding is the process of removing metal by the application of abrasives which are bonded to form a rotating wheel. When the moving abrasive particles contact the workpiece, they act as tiny cutting tools, each particle cutting a tiny chip from the workpiece. It is a common error to believe that grinding abrasive wheels remove material by a rubbing action; actually, the process is as much a cutting action as drilling, milling, and lathe turning. The grinding machine supports and rotates the grinding abrasive wheel and often supports and positions the workpiece in proper relation to the wheel. The grinding machine is used for roughing and finishing flat, cylindrical, and conical surfaces; finishing internal cylinders or bores; forming and sharpening cutting tools; snagging or removing rough projections from castings and stampings; and cleaning, polishing, and buffing surfaces. Once strictly a finishing machine, modem production grinding machines are used for complete roughing and finishing of certain classes of work. Grinding machines have some special safety precautions that must be observed. These are in addition to those safety precautions described in Chapter 1. SAFETY PRECAUTIONS GRINDING MACHINE SAFETY Grinding machines are used daily in a machine shop. To avoid injuries follow the safety precautions listed below . Wear goggles for all grinding machine operations. Check grinding wheels for cracks (Ring Test Figure 5-11) before mounting. Never operate grinding wheels at speeds in excess of the recommended speed. Never adjust the workpiece or work mounting devices when the machine is operating Do not exceed recommended depth of cut for the grinding wheel or machine. Remove workpiece from grinding wheel before turning machine off. Use proper wheel guards on all grinding machines. On bench grinders, adjust tool rest 1/16 to 1/8 inch from the wheel. 5-1 TC 9-524 TYPES OF GRINDING MACHINES From the simplest grinding machine to the most complex, grinding machines can be classified as utility grinding machines, cylindrical grinding machines. and surface grinding machines. The average machinist will be concerned mostly with floor-mounted and bench-mounted utility grinding machines, bufting machines. and reciprocating surface grinding machines. UTILITY GRINDING MACHINES The utility grinding machine is intended for offhand grinding where the workpiece is supported in the hand and brought to bear against the rotating grinding abrasive wheel. The accuracy of this type of grinding machine depends on the operators dexterity. skill, and knowledge of the machines capabilities and the nature of the work. The utility grinding machine consists of a horizontally mounted motor with a grinding abrasive wheel attached to each end of the motor shaft....
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- Spring '10