Abstract: A re-keying process includes inserting a peg (65) into a plug (10) of a cylinder lock to be re-keyed. The peg (65) partially blocks a key slot (18) in the plug (10), thereby preventing the original key (30) to be inserted into the plug (10). A longitudinal groove (75) is then formed on the blade (74) of a key (70), thereby allowing the key (70) to be inserted into the partially blocked key slot (18). To insert the peg (65) into the plug (10), the plug (10) is placed in a bore (45) of a drill block (40). An alignment bolt (61) is used to positioning the plug (10) in the bore (45). A drill bit (62) is inserted into a drill guide hole (52) in the drill block (40) to drill a hole (63) in the plug (10). The peg (65) is then screwed into the hole (63).