5. Increase the torque on the rear top sub until the gap between the rear top sub and the outer casing is eliminated. Adjust the torque according to the diameter of the DTH Drill Hammer. Each inch requires a torque of 1500ft-lb (0.86KN.M per millimeter). For example, the outer diameter of the DHD360 DTH Drill Hammer is 6in (152mm), which tightens the front joint's torque. According to 6 (152) * 1500 (0.86) that is 9000ft-lb (131KN.M).
6. Make sure that the "O" ring on the guideed case is intact, because it can keep the DTH Drill Hammer position of the guideed case fixed when the front top sub is removed, and the guide sleeve is inserted into the outer sleeve to ensure that the guide sleeve is stuck on the outer sleeve, it may be necessary to lightly tap the two sides of the guide sleeve several times with a copper rod.
7. When installing the stop ring, first put the stop ring sideways into the outer casing. When the stop ring is close to the cutout, turn the DTH Drill Hammer stop ring to a suitable position until the stop ring is embedded in the groove of the drill bit. After installing the stop ring When using, be sure to wear eyeglasses to prevent the lubricating oil from splashing into the eyes by inserting the stop ring.
8. Apply a layer of lubricating oil on the spline of the drill bit, and install the front top sub on the dth drill bit.
9. Assemble the stop ring and the "O" ring of the stop ring with the dth button drill bit and the front top sub.
10. Apply a layer of lubricating oil evenly on the thread of the front top sub, and then put the front top sub and the drill bit into the outer casing.
11. Before DTH Drill Hammer drilling, the pre-tightening torque on the front top sub must be in accordance with the specification.
