TM 5-3820-256-10
the kelly in the same manner as it is removed to make a connection, and retracting it into the mast.
(2)
Attach and tighten the hoisting plug to the joint being held in the rotary table; use the auxiliary drum to raise
the drill string to the next tool joint; reset the break-out fork; repeat the breaking-out procedure; then lay the
joint of pipe into the rig tender storage compartment or onto pipe racks (if available).
(3)
Repeat this procedure until all joints of pipe are out and the last drill collar has been removed. If a new bit is
to replace a worn bit, leave the bit sub/ drill collar (or DTH hammer/pipe) joint intact. Otherwise, first
remove the bit (according to the following instructions); then break the sub/drill collar (or DTH hammer/pipe)
joint.
g. Changing the bit: attaching/removing down-the-hole hammer.
(1)
Install the drive plate in the drive sleeve.
(2)
Raise the collar and bit sub until the bit is just below the rotary table, and attach the break-out wrench onto
the bit. Rotate the table (counterclockwise) to break the connection. (Use similar procedures to remove the
button bit from the DTH hammer.) (3) Install the new bit (or if changing to percussion drilling, install the
DTH hammer and button bit). Tighten with the break-out wrench and rotary table.
h. Going into the hole.
(1)
After a new bit (or the DTH hammer and button bit) is installed and tightened, remove the drive plate from
the drive sleeve.
(2)
Operate the auxiliary drum to raise the drill string from the rotary table. Remove the break-out fork and
lower the joint into the hole. Install the break-out fork and allow the joint to rest in the rotary table.
(3)
Remove the hoisting plug, then insert and tighten it into the next joint to be attached to the drill string.
(4)
Raise the pipe joint into the mast, being sure to catch the tailing end of the pipe before it reaches the rotary
table area. Apply the pipe joint compound on the threads; then insert the male pin into the box. Use the
table to screw the joint together; then tighten the joint with the break-out wrench.
(5)
Repeat Steps 3 and 4 until all the pipe joints are installed in the hole. Finally attach the kelly as you would
in making an ordinary connection (adding pipe).
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