EE WAS USING A 4"" HAND-HELD DISK GRINDER TO GRIND METAL IN THE MAINTENANCE SHOP. HE APPLIED PRESSURE AT AN ANGLE TO THE GRINDER WHEN HIS LEFT HAND CAME IN CONTACT WITH THE GRINGING WHEEL. THIS RESULTED IN A 1"" LACERATION TO THE 4TH KNUCKLE OF HIS LEFT HAND WHICH REQUIRED SUTURES.