Abstract: An oxygen-fuel cutting torch having an easily manufactured preheat tube assembly assuring complete mixing of the oxygen and fuel, and minimizing the danger associated with flashback of the flame into the torch. The preheat tube assembly includes an outer tube, an inner tube, a mixer tube, and a nozzle fitting. The inner tube and mixer tube are joined together end to end by the nozzle fitting and are both positioned within the outer tube. A chamber is formed in the oxygen channel at the juncture of the nozzle fitting and the mixing tube for increasing the turbulence of the oxygen prior to mixing with the fuel and to attenuate the shock wave generated by flashbacks.