A tuner for a guitar having a neck and string nut including a plurality of nut slots configured to receive respective guitar strings. A tuner mount is fixedly secured to the neck and a tuner body is mounted on the tuner mount. A string break angle fastener is engageable with a guitar string passing through the respective nut slot and sets a break angle of the guitar string. A string lock carriage is movably mounted on the tuner body and includes a string fastener engageable with the guitar string passing through the respective nut slot to secure the guitar string to the carriage. A tuner knob is manually movable to drive the string carriage and thereby adjust the tension of and tune the respective guitar string.