Page 26 - Moving the Earth_ The Workbook of Excavation

LAND CLEARING AND CONTROLS

1.26 THE WORK

Alloy steel chains weigh only about one-third as much as standard chains in proportion to
strength. If a crew is careful enough not to lose chains, and is conscientious enough not to abuse
them by kinking or gross overloading, alloy chains will amply repay their much higher cost in
reduced labor and fatigue, and by greater efficiency.
3
As an example, one ⁄ 8 -inch alloy chain, weighing 1.6 pounds per foot, is 30 percent stronger
5
than the same make of ⁄ 8 -inch ordinary chain, weighing 4.1 pounds per foot.
It is recommended that the alloy chain be dipped in bright red paint so that it can be easily rec-
ognized, and recovered readily if mislaid.
Cables. Only the method shown in Fig. 1.19A, part (B), should be used in pulling a stump with
a cable choker, as the sharp bends involved in the others will cause early breakage of the cable.
If a double cable line is used to reduce strain, or to shorten the rope, it should not be bent
around sharp angles. A stump is generally round and smooth enough not to cut a cable wrapped
around it, and the end hooks or loops can be attached to the drawbar. If the load is angular, it is
better to fasten a snatch block to it with a chain or sling choker, and to run the long cable through
the block pulley.
If a double cable is so wrapped around the load that it cannot slide around it, great care must
be taken to adjust it so that both ends share the strain equally, unless a single line is strong enough
to take the entire pull alone.
Root Hook. A root hook may be used when a stump is too big to pull directly. Enough soil is
dug away to expose the lateral roots, the hook is placed to grip one of these, power is applied, and
the root is torn out. This process is repeated until the stump is sufficiently weakened to be taken
out on one of the root pulls, or by direct pull on the butt.
The root hook may also be laid on top of a stump, with the teeth in a notch on the back. A pull
on this gives excellent leverage, but the edge of the stump is liable to tear off. See Fig. 1.19B.

Taproots. The presence of a taproot increases resistance of the stump. If the ground is hard, this
root may be broken or pulled apart. If the ground is soft, or the wood very tough or pliable, the pivot
point may crush and the root bend so that the pulling power is exerted directly against the length
of the root, without benefit of leverage. In such a case, the upper roots of the stump may be torn
up sufficiently so that an axe, or a special long chisel, can reach and cut the taproot. The cut should
be made while pulling, as tension makes the wood part more easily.

Pulling Clear. If the force is sufficient to uproot a stump, the roots opposite the pull break first,
then those at the side, permitting the stump to be pulled onto its side. If the line does not slip off,
the stump may be rolled and dragged out of the ground, but this often takes much more power than
overturning the stump, and may be beyond the capacity of the machine that is doing the pulling.
If the stump will not come all the way, the line may be slacked and a log placed or chained
against the stump, as in Fig. 1.20. This log will provide a new fulcrum and aid the breaking out.
Or the line may be taken off and the tractor moved to pull in the opposite direction, which should

FIGURE 1.19B Root hook.