KKQ4 series hole opener is a three or four cone hole opener. The mandrel is same with the manufacturing technology of KKQ series. All the front plate, middile bowl, rear plate and strenghten rib are connected with mandrel reasonablely and welded with mandrel tightly, which makes the structure more steadily. All the four cones improve the efficiency of hole opening.Type Hole Dia. Blade No. Min. guiding hole Mandrel Fishing neck Diameter Mandrel I.D. Upper threads (Pin thread) Lower threads ( Box thread) Overall Length KKQ311 12 1/4 ´ 3 8 1/2 ´ 8 ´ 1 1/2 ´ 6 5/8 REG 6 5/8 REG 60 ´ KKQ406 16 ´ 3 10 ´ 9 1/2 ´ 2 1/4 ´ 7 5/8 REG 7 5/8 REG 72´ KKQ444 17 1/2 ´ 3 10 ´ 9 1/2 ´ 2 1/4 ´ 7 5/8 REG 7 5/8 REG 72 ´
