Document DanybOaXO8QqLRDdwgN4NR4d

BENCH AND STAND GRINDERS DRESSING 1 Wear a face shield over your safety glasses for protection against heavy particles 2 Use a dressing tool approved for the job Never use a lathe cutting tool 3 Inspect star dressers for loose shaft and worn disks 4 Round off the wheel edges with a hand stone before and after dressing to prevent the edges from chipping 5 Use the work rest to support and guide the tool Use a tool holder if one is available 6 Apply moderate pressure slowly and evenly 7 Always apply diamond dressers at the cen ter or slightly below the center, never above Fic 31-25 --Major safety measures to be taken in a wheel dressing operation cedures should be followed Stones of un known composition or manufacture should never be run more than 2500 sfpm and ordi narily not more than 2000 sfpm The size and weight of grmdstones require a stand that is rigidly constructed, that is heavy enough to hold the stone securely, and that is mounted on a solid foundation to with stand vibration Since grindstones are run wet, all possible precautions should be taken to prevent slip ping accidents near the stones Rough con crete or other nonslad floor material is recom mended Grindstones should be carefully inspected for cracks and other defects as soon as they are received from the manufacturer Those not to be used at once should be stored m a dry, uniformly heated room In storage they should be placed so that they will not be damaged Many grindstone failures result from faulty handling and from incorrect methods of mounting Gnndstones should not be left partially submerged in water This practice causes an unbalanced stone that may break when rotated Wooden wedges should not be used on power-driven stones Often, such wedges are dnven excessively tight or become wet and swell In either case, cracks start m the comers of a square center hole, radiate outward, and so weaken the stone that rup tures occur at normal speed After the stone has been centered, the cen tral space about the arbor should be filled with lead or cement Double thicknesses of leather or rubber gaskets, rather than wood washers, should be used wherever possible If wood washers are used between the flanges and the stone, the washers should be J- to 1-m thick and the flanges should be clamped in place by heavy nuts Work rests should comply with the same conditions as those for grinding wheels For dressing or operating power-dnven gnndstones (either wet or dry), exhaust sys tems should be provided to remove dust and wet spray or mist Polishing and buffing wheels Polishing wheels are either wood wheels faced with leather or wheels made of disks of canvas or similar matenal stitched together, with a coat of emery or other abrasive glued to the periphery of the wheels Buffing wheels are made of disks of felt, linen, or canvas, and the periphery is given a Fic 31-26 --Guarding and exhaust provisions for a surface grinding operation 853