Machinery's Handbook, 31st Edition
1320 CYLINDRICAL GRINDING 3) Wheel out of round: True before and after balancing. True sides to face. 4) Wheel too hard: Use coarser grit, softer grade, more open bond. See Wheel Defects on page 1322. 5) Improper dressing: Use sharp diamond and hold rigidly close to wheel. It must not overhang excessively. Check diamond in mounting. 6) Faulty work support or rotation: Use sufficient number of work rests and adjust them more carefully. Use proper angles in centers of work. Clean dirt from footstock spindle and be sure spindle is tight. Make certain that work centers fit properly in spindles. 7) Improper operation: Reduce rate of wheel feed. 8) Faulty traverse: See Uneven Traverse or Infeed of Wheel Head on page 1322. 9) Work vibration: Reduce work speed. Check workpiece for balance. 10) Outside vibration transmitted to machine: Check and make sure that machine is level and sitting solidly on foundation. Isolate machine or foundation. 11) Interference: Check all guards for clearance. 12) Wheel base: Check spindle bearing clearance. Use belts of equal lengths or uniform cross section on motor drive. Check drive motor for unbalance. Check balance and fit of pulleys. Check wheel feed mechanism to see that all parts are tight. 13) Headstock: Put belts of same length and cross section on motor drive; check for cor rect work speeds. Check drive motor for unbalance. Make certain that headstock spindle is not loose. Check work center fit in spindle. Check wear of faceplate and jackshaft bearings. Spirals on Work (traverse lines with same lead on work as rate of traverse): Sources of spirals include: 1) machine parts out of line; and 2) truing. Suggested procedures for correction of these troubles are: 1) Machine parts out of line: Check wheel base, headstock, and footstock for proper alignment. 2) Truing: Point truing tool down 3 degrees at the workwheel contact line. Round off wheel edges. Check Marks on Work: Sources of check marks include: 1) improper operation; 2) improper heat treatment; 3) improper size control; 4) improper wheel; and 5) improper dressing. Suggested procedures for correction of these troubles are: 1) Improper operation: Make wheel act softer. See Wheel Defects . Do not force wheel into work. Use greater volume of coolant and a more even flow. Check the correct posi tioning of coolant nozzles to direct a copious flow of clean coolant at the proper location. 2) Improper heat treatment: Take corrective measures in heat-treating operations. 3) Improper size control: Make sure that engineering establishes reasonable size limits. See that they are maintained. 4) Improper wheel: Make wheel act softer. Use softer-grade wheel. Review the grain size and type of abrasive. A finer grit or more friable abrasive or both may be called for. 5) Improper dressing: Check that the diamond is sharp, of good quality, and well set. Increase speed of the dressing cycle. Make sure diamond is not cracked. Burning and Discoloration of Work: Sources of burning and discoloration are improper operation, and improper wheel. Suggested procedures for correction of these troubles are: 1) Improper operation: Decrease rate of infeed. Don’t stop work while in contact with wheel. 2) Improper wheel: Use softer wheel or obtain softer effect. See Wheel Defects . Use greater volume of coolant.
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