Modular bench for assembly and in-line handling of curtain wall frames. It is provided with two roller tracks covered with soft PVC sheathing; the distance between the two tracks is adjustable according to the width of the curtain wall section. A pneumatically operated system allows clamping the rollers during the work phases. The entire bench can be rotated by 360° in order to facilitate the assembly and sealing of the curtain wall; the angular position is clamped pneumatically.