A method of producing an assembly tool (60) for assembling an assembly (6), the method comprising: providing at least a portion of a jig frame (62); fixing support plates (65) to the jig frame (62); machining the one or more support plates (65) such that a surface of each of the support plates (65) lies in a common plane (130); positioning the jig frame (62) such that the machined surfaces of the support plates (65) contact with a supporting surface (138); fixing pickup device mounting plates (140a, 140b) to the jig frame (62); machining, with respect to the supporting surface (138), the pickup device mounting plates (140a, 140b) such that a surface of each mounting plate (140a, 40b) has a respective predetermined position and orientation with respect to the supporting surface (138); and fixing, to the machined surfaces of the mounting plates (140a, 140b), a respective pickup device (66-72).