Abstract: An apparatus is provided for hard facing by powder flame spraying of inner surfaces of bores of relatively large workpieces difficult to mount rotatably, such as Diesel engine blocks, and the like. The apparatus comprises a stand, a carriage support pivotally and mounted to the stand via a holding mechanism coupled to the stand and adapted to be adjustably inclined and to move vertically between a pair of supporting columns of the stand. A carriage is mounted on the carriage support and has a burner assembly mounted to and extending transversely from the carriage, the burner assembly comprising a burner mounting having a longitudinal member extending therefrom through which powder flame spray material is fed, the member terminating into a nozzle disposed transverse to the longitudinal axis of the longitudinal member. The carriage is slidably mounted on the carriage support and has a mechanism associated therewith for sliding the carriage along the axis of the longitudinal member.