1. Speical machine for drilling of H-beam and box girder 2. It can drill the 3 sections of H beam at the same time, workpiece is infeeded and outfeeded on the machine's infeeding conveyor and outfeeding conveyor. 3. The maximum drilling diameter is 33.5MM 4. Drilling heads' stroke is controlled automatically, with professional spindle reducer motor imported from Germany. 5. PLC plus upper computer controlled, CRT display, easy for programming and convenience for preview.