Listed below are problems, which may be encountered whilst grinding. Possible corrections are used advisedly here. It is practically impossible to establish hard and fast rules for turning out perfect grinding. There are many variables, which must be correctly attuned and an apparently irrelevant one may prove to be cause of trouble experienced. Also, the same cause may produce a varied number of grinding problems.
 
Scratch Marks
SCRATCH MARKS ON WORK
  • Improper work support blades
    Change blade to a softer material; if tungsten carbide was used,
    try steel, cast iron or aluminium bronze.
  • Wide irregular marks, varying in depth, from too soft a wheel
    Use harder grade wheel.
  • Widely spaced spots on work piece due to oil or glazed spots on wheel
    True spots out of wheel, balance and redress.
    Avoid getting oil on wheel.
  • Even fine spiral diamond lines
    Dress at slower traverse rate.
    Turn diamond frequently.
    Diamond cracked or broken; replace.
    Turn diamond frequently.
    Diamond cracked or broken; replace.
    Diamond holder loose; tighten clamping screw.
    Try lighter diamond cuts.
    Make final dressing in opposite direction to initial runs.
  • Even spiral lines on work piece whose lead corresponds to feed rate.
    Dress wheel face parallel to work piece to prevent leading or trailing edge from digging in.
    Use crowned cam when dressing grinding wheel.
    Cut back front of face of wheel approximately half of stock removal over 1" distance for a six-inch wheel (relatively more on wider wheels)
    Increase or decrease successive traverse rates to break pattern of diamond lines. When throughfeed grinding, make certain guides on regulating wheel side are parallel and even with wheel face.
  • Uneven fine lines on work piece due to faulty dressing
    Do not allow diamond to dwell on wheel. Barely contact wheel face at high spot—dress across face only, starting at an edge, do not start on face. Maintain diamond traversing at an even rate.
  • Uneven, or evenly spaced lines on work piece due to extraneous vibrations
    If impossible to change machine location, mount grinder on some vibration insulating material. Be certain insulation is thick enough to be effective.
    If it is not sufficient, the natural frequency of grinder normally damped out by rigid construction may be emphasised and combine with external vibration to make conditions worse.
  • Wavy traverse lines due to faulty dressing, leaving ragged wheel edges.
    Round off wheel edges nicely—chamfering or dressing back is not sufficient.
  • Irregular grit marks as result of wheel bond’s disintegrating. ("Fish Tails".)
    Try a different coolant, or if soluble oil used, cut down soda content of coolant. High soda concentrations attack resinoid and shellac bonds. Wheel too soft—use harder grade.
  • Coarse grains or foreign matter in wheel face.
    Dress these out of wheel.
    Determine whether caused by type of wheel, dull diamond, dirty or too strong a coolant.
  • Irregular scratches of various lengths and sizes due to dirty coolant. ("Fish tails.")
    Empty and clean tank, lines, guards, etc. Flush guards and wheel after each truing. Use coolant filter for fine finishes.
  • Too great a difference in grain size between roughing and finishing wheels.
    Dress roughing wheel at slower traverse rate.
    If this doesn’t help, try a finer cut with roughing wheel.
  • Deep irregular marks caused by loose wheel.
    Use one standard paper washer (blotting paper if other not available) under flanges and tighten down.
  • Isolated deep marks due to improper dressing.
    Rotate or change diamond to—get sharper dressing. Wash wheel thoroughly with coolant after dressing. Reset gib on truing device.
  • Grain marks due to too soft or coarse a wheel.
    Substitute harder grade or finer grained wheel
  • Rough uneven finish.
    Diamond cracked or broken; replace.
  • Regulating wheel too hard.
    If regulating wheel too hard, work will spin and score on blade but it would be practically impossible to grind.
  • Wheel too smooth.
    Reset diamond or use new one. Use coarser or softer wheel.
  • Roughing wheel breaks down too fast.
    Rough grind with more and smaller cuts, or use harder wheel for roughing.
Vibration
Chatter Marks
Low Ends
Low Centre
Not Straightened
Work Out of Round
Faulty Sizing
Wheel Loading
Wheel Glazed
Wheel Grading
Wheel Breakage
Maintenance Tips

 
 

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