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. SAFETY PRECAUTION
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.
TYPES OF GRINDING MACHINE
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