Abstract: A carpenter's hammer wherein the handle portion is telescopic using two slidably mating tubes. Two optimal preset positions are made possible by means of a dual spring-nipple. At the 14.5? stop, the jig hammer can be used to jig the position between studs for 16? on center. At the 16? stop, the jig hammer can be used to mark stud locations on wall plates prior to nailing, as well as to locate studs once panel board covers these studs. A built-in safety bar serves as a positional stop, and also to prevent separation of the two telescopic handle portions. A pencil holder at the extremity of the handle portion positions a pencil through the handle in such a manner as to allow marking at the very end of said hammer.