EMPLOYEE WAS REMOVING A BROKEN WELD FROM A PIVOT POINT ON A FRONT END LOADER WITH A 4 1/2"" HAND HELD GRINDER. HE WAS WORKING IN A SEMI-CONFINED SPACE. THE GRINDER WAS FITTED WITH A GRIP HANDLE ON LT. SIDE, BUT THE GRINDING WHEEL GUARD WAS NOT BEING USED. THE GRINDING WHEEL JUMPED & HIS LT. INDEX FINGER CAME IN CONTACT WITH THE WHEEL.