... 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 ... the hole diameter: Φ 31 mm, Φ 13.5 mm, Φ 9.8 mm5, drilling time:<=40s6, the machine quality: 23 kg7, physical ...