The damage to copper crystals, produced by spark planing operations, has been measured using a dislocation etch pit technique.The tabulated results show the depth of damage to vary from 0.7 - 1.1 mm on the coarsest planing range used to 0.2 - 0.3 mm on the finest range.Two photomicrographs showing the etch pit density increase near the spark planed surface are included. (Author).