88 
BULLETIN" 711, U. S. DEPARTMENT OF AGRICULTURE. 
made in this manner, and it has become standard for general work. 
In the latter, the wires in the strand and the strands in the ropes 
are twisted in the same direction. 
Wire ropes are made almost exclusively from iron or steel, and 
the materials used may be further grouped into three main divi- 
sions, viz, iron, crucible cast steel, and plow steel. The wire rope 
used for yarding lines is for the most part made from plow steel 
and special plow steel. These two classes of rope, besides being 
used for main, trip, and straw lines, are used for chokers and over- 
head yarding lines, the special plow steel being especially adapted 
for overhead work. For lines other than chokers a 6 by 19 con- 
struction with a hemp core is used. A small percentage of operators 
make their main yarding lines from rope that has a steel core. 
The diameter and length of lines is discussed under the heading 
" Wire rope cost." 
The selling price of wire rope, besides varying with the grade and 
type of construction, fluctuates with economic conditions. The list 
prices of manufacturers for the same grade and construction are 
the same. On March 8, 1916, the discount quoted by one wire- 
rope agent was 37-J per cent off the list prices. About two years 
ago the discount was about 60 per cent. Under normal conditions 
the discount is about 50 per cent. 
The following tables give the net prices on wire rope of the 
grade and type of construction ordinarily used in logging opera- 
tions. The prices are based on a discount of 50 per cent off the list. 
The strengths given are standard, being those adopted by the manu- 
facturers on May 1, 1910. 
Table 12— Standard ploiv steel hoisting rope. 
[6 strands, 19 wires to the strand, 1 hemp core.] 
Approxi- 
mate 
weight 
per foot in 
pounds. 
Approxi- 
mate 
Proper 
working 
Net price 
] diameter 
strength 
load in 
per foot. 
in inches. 
in tons of 
2,000 
pounds. 
tons of 
2.000 
pounds. 
$0.06 
^ 
0.10 
2.65 
0.53 
. 06025 
A 
.15 
3.8 
.76 
.0625 
f 
.22 
5.75 
1.15 
.065 
& 
.30 
8 
1.6 
.07 
i 
.39 
10 
2 
.08 
9 
T5 
.50 
12.3 
2.4 
.095 
1 
.62 
15.5 
3.1 
. .13 
3 
4 
.89 
23 
4.6 
.17 
1 
1.20 
29 
5.8 
.215 
1 
1.58 
38 
7.6 
.27 
14 
2 
47 
9.4 
.325 
i) 
2.45 
58 
12 
.395 
3 
72 
14. 
.465 
li 
3.55 
82 
16 
.54 
11 
4.15 
94 
19 
.65 
4.85 
112 
22 
.73 
n 
5.55 
127 
25 
.79 
2 
6.3 
140 
28 
Note. — The net prices given are based on a discount of 50 per cent off the list prices. Add 10 per cent 
to the list prices for wire center. 
