86 
BULLETIN 711, U. S. DEPARTMENT OF AGRICULTVRE. 
Trip-line head blocks (Fig. 22), 
No. 
Sheave. 
Pin. 
Hub. 
Weight. 
Xet price. 
2 
3 
Inches. 
14 by H 
18 by If 
24 by 2 
Inches. 
2£ 
2i 
3 
Inches. 
3 
4 
5 
Pounds. 
95 
140 
235 
S17. 60 
26.00 
44.00 
Extra parts. 
Net price. 
Items. 
No. 1. No. 2. No. 3 
Forged-steel shackle » $1. 20 
Pair steel block sides 
Casehardened steel pin 
Oil cup and nut with lock washer 
Half nut wit h lock washer 
Bronze bushing 
Manganese-steel sheave, bronze bushed 
.20 
2.00 
.60 
.40 
1.60 
7.60 
SI. 60 
9.60 
2.60 
.60 
.45 
2.00 
12.20 
S2.S0 
18.80 
3.20 
1.40 
.60 
3.60 
20.00 
1 No. 3 has tool-steel forged shackle. 
Table 11 gives the fixed investment in ground yarding blocks for 
one yarding engine. To allow for a proper range, the total cost and 
weight, including blocks of different sizes, is shown in three cases. 
The aim is to include a liberal amount of such equipment, taking into 
account the fact that the number of blocks needed for different yard- 
ing chances varies and that some blocks are undergoing repairs at 
times. This table can be easily modified to take care of a given set 
of conditions. 
Table 11. — Fixed investment in blocks for one yarding engine. 
Items. 
Butt chain blocks. . . 
Moving blocks 
Yarding blocks 
Head trip block 
Corner or side block. 
Side blocks 
Extra parts 
Case 1. 
Case 2. 
Case; 
24bv8 
16 by 3 
12 by 2h 
24 bv 2" 
14byU 
12byli 
za 
1,640 
540 
290 
235 
96 
440 
400 
Total , 3,640 666.00. 
I I 
$256.00 20 by 
00 
53.60 
44.00 
17.60 
96.00 
100. 00 
14 by 3 
10 by 2k 
18 by if 
14 by U 
12byli 
1,300 8204.00' 16 by 7 
460 
220 
140 
95 
44i' 
300 
90. 00| 14 bv 3 
45.60' 10bv2i 
26.00 14bvU 
17. 60, 14 by 1J 
96. 00| 12 by li 
75. 00 
.1 2,955 554.00 j 2,510 460.00 
-5144. 00 
90.00 
45.60 
17.60 
17.60 
96.00 
50.00 
' Prices are those of March, 1916. 
Yarding rollers. — Figure 28 shows a yarding or stump roller. 
The use of such rollers in connection with ground yarding is dis- 
cussed on page 72. The method is also shown in figure 15. They 
weigh from 210 to 325 pounds and cost from $45 to $60. 
Ground yarding lines. — Ground yarding lines are all made of wire 
rope, without which modern methods of logging could not have 
developed. Wire rope consists of a group of strands laid sym- 
