Abstract: A cylinder lock has a socket portion formed integrally with the rear end of its cylinder for connection with a flat stamped shaft. The shaft has an enlarged head at its front end and a medial enlargement defining forwardly facing shoulders. The socket has a cavity in which the shaft head is rotatable, a noncircular bore opening rearwardly from the cavity through which the head can be inserted forwardly into the cavity in one position of shaft rotation, and grooves opening forwardly to the cavity in which the head is receivable upon rearward motion of the shaft in another position of its rotation. A coiled expansion spring reacting between said shoulders and the rear of the socket confines the head in said grooves.