used kent 3 axis automatic surface grinder SGS-1020AHD used kent 3 axis automatic surface grinder SGS-1020AHD used kent 3 axis automatic surface grinder SGS-1020AHD used kent 3 axis automatic surface grinder SGS-1020AHD used kent 3 axis automatic surface grinder SGS-1020AHD used kent 3 axis automatic surface grinder SGS-1020AHD