STANDARD HANDBOOK OF PETROLEUM & NATURAL GAS ...

596 Drilling and Well Completions
The first clip should be attached at a point about one base width from the
last seizing on the dead end of the rope and tightened securely. The saddle of
the clip should rest upon the long or main rope and the U-bolt upon the dead
end. All clips should be attached in this manner (see Figure 4-74). The short
end of the rope should rest squarely upon the main portion.
The second clip should be attached as near the loop as possible. The nuts
for this clip should not be completely tightened when it is first installed. The
recommended number of clips and the space between clips are given in Table
4-33. Additional clips should be attached with an equal spacing between clips.
Before completely tightening the second and any of the additional clips, some
stress should be placed upon the rope in order to take up the slack and equalize
the tension on both sides of the rope.
When the clips are attached correctly, the saddle should be in contact with
the long end of the wire rope and the U-bolt in contact with the short end of
the loop in the rope as shown in Figure 4-72. The incorrect application of clips
is illustrated in Figure 474.
The nuts on the second and additional clips should be tightened uniformly,
by giving alternately a few turns to one side and then the other. It will be found
that the application of a little oil to the threads will allow the nuts to be drawn
tighter. After the rope has been in use a short time, the nuts on all clips should
be retightened, as stress tends to stretch the rope, thereby reducing its diameter.
The nuts should be tightened at all subsequent regular inspection periods. A
half hitch, either with or without clips, is not desirable as it malforms and
weakens wire rope.
Figure 4-75 illustrates, in a simplified form, the generally accepted methods
of reeving (stringing up) in-line crown and traveling blocks, along with the location
of the drawworks drum, monkey board, drill pipe fingers, and deadline anchor
in relation to the various sides of the derrick. Ordinarily, the only two variables
in reeving systems, as illustrated, are the number of sheaves in the crown and
traveling blocks or the number required for handling the load, and the location
of the deadline anchor. Table 4-34 gives the right-hand string-ups. The reeving
sequence for the left-hand reeving with 12 lines on a seven-sheave crown-block
and six-sheave traveling block illustrated in Figure 4-75 is given in Arrangement
No. 1 of Table 4-34. The predominant practice is to use left-hand reeving and
- INCOR R EC T-/
Figure 4-74. Incorrect methods of attaching clips to wire rope [ll].