Abstract: The present invention provides a method of making a frame, particularly for the aircraft industry, having a central member (34) and one or more cantilever ribs (32); such a frame can be made by forging or machining but these are time-consuming and expensive. According to the present invention such frames are made by diffusion bonding and superplastic forming techniques, whereby a pack of sheets are bonded together except in certain areas. Gas is injected into those areas to inflate the pack superplastically to form one or more closed cells (16). The top of the cells is then machined off along line 23, while the side walls of the cells are retained, to provide a frame having cantilever ribs (32).

Abstract: The present invention provides a method of making a frame, particularly for the aircraft industry, having a central member (34) and one or more cantilever ribs (32); such a frame can be made by forging or machining but these are time-consuming and expensive. According to the present invention such frames are made by diffusion bonding and superplastic forming techniques, whereby a pack of sheets are bonded together except in certain areas. Gas is injected into those areas to inflate the pack superplastically to form one or more closed cells (16). The top of the cells is then machined off along line 23, while the side walls of the cells are retained, to provide a frame having cantilever ribs (32).

Abstract: A mechanical hole digging machine comprising a rotary cutting tool and a suction tube having an inlet opening adjacent to the cutting tool, a suction device for applying suction to the tube remote from the inlet opening to cause material cut away by the cutting tool to be sucked inwards through the inlet opening, the cutting tool and part at least of the suction tube being carried on a mounting by which they are movable upwards and downwards. An electromagnetic metal detector comprising three coils is mounted near the cutter head and adapted in use to give an indication of the presence of buried metal service pipe during a hole digging operation.