... whole structure is compact, rail clamping device with self-locking function, accurate positioning, drilling high precision. The hollow bit, ... drilling with automatic feed water function, is works departments maintenance, repair and overhaul operations necessary ... min4, the hole diameter: Φ 31 mm, Φ 13.5 mm, Φ 9.8 mm5, drilling time:<=40s6, the machine quality: 23 kg7 ...