... 42mm 3.High drilling efficiency,long life PDC drilling bit PDC drill bit manufactured by Zhengzhou LD Diamond Products CO.,Ltd, ... by micro-chipping. Compared to tungsten carbide bit, cone bit, diamond impregnated bits, the PDC bit has increased efficiency and longer life.Our ... carbide 2. Skillful welding technology 3. Good controlling cost, best price for our customer 4. Fast delivery 5.Model: various ...