Abstract: A self-actuating thermal disconnect disengages two coaxially aligned shafts if equipment driven by one of the shafts overheats. The disconnect uses the centrifugal force of a molten material as the principal actuation. The disconnect end of a drive shaft has a means for transmitting torque. A disconnect piston having first and second ends is axially movable in a splined cylinder within the driven shaft. In normal operation, a solid mass of fusible material is disposed in the disconnect piston within a cavity defined by the second end of the disconnect piston and an adjacent end of a cavity piston. A means for transmitting torque at the-first end of the disconnect piston couples with the means for transmitting torque at the first end of the drive shaft. If the driven equipment overheats, the molten fusible material bursts out under centrifugal force through the channels.