A cylinder lock assembly includes a cylinder body and a plug assembly which is manufactured in a multiple of pieces to facilitate casting of each plug piece in a single operation. The plug assembly includes a plug body with a plug insert opening to receive a plug insert. The plug insert opening is generally L-shaped in cross-section to receive the plug insert which is correspondingly shaped. The plug insert includes a plug outer portion which defines an arcuate outer surface which corresponds with the outer circumference of the plug body when the plug insert is mounted therein. A plug pin chamber portion extends generally transverse to the plug outer portion to define a multiple of tumbler pin chambers which extend through the plug outer portion.