起拔钻孔内的套管有时是要个别地割断而起拔的。由于水压割管器构造比较复杂,所以目前应用不广泛。建议用如图所示的、以废钻杆制成的“自磨式割管器”。它的结构是由直径为42毫米的钻杆(3),中间焊上割刀环(2),环上具有四组割刀(1)构成。 Pull up the casing within the hole is sometimes individually cut and raised. Due to the structure of hydraulic cutter is more complex, so the current application is not extensive. It is recommended to use the “self-grinding pipe cutter” made of waste drill rod as shown in the figure. Its structure is composed of a drill rod (3) with a diameter of 42 mm, a cutter ring (2) welded in the middle, and four cutter sets (1) in the ring.