GRINDING ISSUE CAUSES CORRECTION

Chatter

Faulty coolant Clean coolant tank and lines. Replace dirty or heavy coolant with correct mixture
Out-of-Balance Rebalance on mounting before and after dressing.
Run wheel without coolant to remove excess water.
Store a removed wheel on its side to keep retained water from causing a heavy side.
Tighten wheel mounting flanges
Make sure wheel center fits the spindle
Wheel out of round True before and after balancing.
True sides and faces
Wheel too hard Use coarser grit, softer grade, more open bond
Improper dressing Use sharp diamond and hold rigidly close to the wheel. It must not overhang too far
Check diamond in mounting for rigidity
Faulty work support or rotation Use sufficient number of work rests, one every 9 inches of work length, and adjust them more carefully.
Use proper angles in work centers
Clean dirt from footstock spindle and be sure spindle is tight
Make certain that work centers fit properly in spindles
Improper operation Reduce rate of wheel feed
Work vibration Reduce work speed
Check workpiece for balance
Outside vibration transmitted to machine Check and make sure that the machine is level and sitting solidly on foundation
Isolate machine and foundation
Interference Check all guards for proper clearance
Wheelhead 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 mechanisms to see that all parts are tight
Headstock Incorrect 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 (traverse lines) on workpiece with same lead as the rate of traverse

Machine parts out of line Check wheelhead, headstock, and footstock for proper alignment
Truing Point truing tool down 3 degrees at the work-wheel contact edges
Make edges of face round

Check marks of workpiece

Improper operation Do not force wheel into work
Use greater volume of coolant and more even flow
Affirm the correct positioning of coolant nozzles to direct a copious flow of coolant to the wheel-work interface
Improper wheel Make the wheel act softer. Use a softer grade wheel
Review the grain size and type of abrasive. A finer grit or more friable abrasive, or both, may be called for.
Improper dressing Make sure you have a sharp, good quality diamond that is well set
Increase speed of the dressing cycles
Make sure the diamond is not cracked

Burns or discoloration of work

Improper operation Decrease rate of infeed
Do not stop work while in contact with wheel
Improper wheel Use softer wheel or obtain soft effect
Use greater volume of coolant
Improper dressing Check dressing tool for sharpness
Increase speed of dressing cycle
 

Isolated deep scratches on work

Improper wheel Use finer wheel and consider a change in abrasive type
Improper coolant and/or coolant filter Use coolant that settles chips
Check coolant filter

Fine spiral or thread scratches on work

Improper operation Reduce wheel pressure
Use more work rests
Reduce traverse with respect to work rotation
Use different traverse rates to break up pattern when making numerous passes
Keep edge of wheel from penetration by dressing wheel face parallel to work
Faulty wheel dressing Use slower or more even dressing traverse
Set dressing tool at least 3 degrees down and 30 degrees to the side from time to time
Tighten holder
Do not take too deep a cut
Round off wheel edges
Starting dressing cut from wheel edge may help

Narrow and deep regular marks

Wheel too coarse Use finer grain size

Wide irregular marks of varying depth

Wheel too soft Use harder grade of wheel

Widely spaced spots on work

Oil spots or glazed areas on wheel face Balance and true wheel
Keep oil from wheel face

Irregular “fishtail” marks of varying lengths and widths

Dirty coolant Clean tank frequently
Use filter for fine-finish grinding
Flush wheel guards after dressing or when changing to a finer wheel