TM 9-6115-604-34NAVFAC P-8-633-34Figure 9-46. Grooved Sidewall Grinding Wheel(a) Use a grooved grinding wheel to specifications 6A-60K6-V22. Each side wall of the wheel shall haveradial grooves approximately 0.125 inch (3.18 m) deep and spaced about 2 inches (50.8 mm) apart atthe face (Figure 946). The grooves help prevent grinding wheel loading, and effectively reduce grindingtemperatures.(b) The wheel guard must have an efficient air baffle and side washer equipment (Figure 9-47). Grindingwheels are porous and centrifugal forces tend to pump air through the wheel and blow the coolant awayfrom the grinding area. The air baffles and side washers supply coolant to displace the air being pumpedthrough the wheel.(c) The grinding machine coolant flow must be sufficient to supply the side washers and main jet with anample volume of coolant.(d) The procedural steps, that must be observed to reduce the risk of grinder bum damage are as follows:1When feeding the grinding wheel into the journal bossing wall, do not exceed a feed rate of0.001 inch (0.025 mm) per second.2The grinding wheel surface speed shall be 6500 feet (1981 m) per minute with the crankshaftrotating at 50 rpm.WARNINGGrinding operations create airborne, abrasive dust, and particles. Respiratory and eye protectionis required to prevent Injury to personnel.(2)Dress grinding wheel. Dress the radii of the grinding wheel to blend smoothly with the sides and face of thewheel. Failure to properly dress the radii will result in a small barely visible groove in the wheel. This willform a stress riser in the journal that can lead to breakage of the shaft. Dress the grinding wheel as follows:(a)Use an industrial diamond in the wheel dresser that has been lapped to a cone having a 75 degreesincluded angle with a point radius of 0 .005 to 0.025 inch (0.001 to 0.64 mm). The point of the cone isto be on the centerline of the shank (Figure 9-48).NOTEThe point of the diamond must be on a radial line from the pivot center of the dressing device sothat the radii generated on the grinding wheel will blend smoothly to both the side and face ofthe wheel. The dressing tool must have stops to limit the travel of the diamond point to exactly90 degrees to the face and sides of the wheel (Figure 9-49).9-84
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