Continuous drive and stored energy (inertia) friction welding systems have not been so successfully exploited for joining long hollow sections where restrictions in the bore cannot be tolerated. Unfortunately ovality, lack of concentricity, and straightness of parts further aggravate the situation. Also there are engineering aspects, such as power transmission and load reaction, which make problematic the rotation and hence friction welding of long hollow sections. A new approach termed radial friction welding was put forward in 1975 which provided a means to overcome these limitations. Potential applications for this technique are indicated in the article.