... 4" inch 311mm drag bit/pdc drag drill bit for water well drilling 1.ISO9001:2000 2.Wings/Blade: 3, ... ≤6, like mudstone, shale, sandstone, etc. mainly used for drain hole, grouting hole, geological and hydrology drilling, Usually ... ensure the bits hve high abrasion resistance, fast drilling speed and long life.Our drag bits can meet your ... inch 311mm drag bit/pdc drag drill bit for water well drilling