30 
BULLETIN 300,, U. S. DEPARTMENT OF AGRICULTURE. 
Table 1. — Cost of operation of single-bucket templet excavator on a ditch in Southern 
Louisiana — Continued. 
Month. 
Exca- 
vation. 
Cost 
per 
cubic 
yard. 
Dis- 
tance 
exca- 
vated. 
Total 
number 
days 
■worked. 
Actual 
number 
days 
digging. 
Average 
length 
dug per 
day. 
Maxi- 
mum 
length 
dug per 
day. 
Aver- 
age 
depth. 
Maxi- 
mum 
depth. 
Cubic 
yirds. 
4,175.9 
10,559.0 
7, 303. 
10,151.2 
10,938.5 
Cents. 
0.076 
.080 
.101 
.077 
.075 
Feet. 
1,115 
1,785 
1,200 
1,850 
1,875 
16 
30 
26 
29 
27 
9.45 
18.7 
10.8 
18.1 
16.3 
Feet. 
120.5 
95.4 
111.1 
102.3 
115. 03 
Feet. 
195 
140 
114 
120 
135 
Feet. 
3.63 
5.62 
5.57 
5.10 
5.38 
Feet. 
5.30 
7.00 
6.70 
May 
5.80 
6.10 
Total or av'g 
43, 127. 6 
.081 
7,825 
128 
73.35 
106. 60 
195 
5.06 
7.00 
THE WHEEL TYPE OF EXCAVATOR. 
The wheel excavator consists of a steel frame mounted on wheels, 
which supports on the front end an engine and boiler and on the rear 
end a pivoted steel framework holding the digging wheel, as shown 
in Plate VII, figure 1. This excavating wheel revolves upon anti- 
friction wheels placed just outside the rim of the wheel. The exca- 
vating scoops or buckets are placed on the circumference of this 
whesl. The front of each scoop is provided with a cutting edge, 
which slices a thin layer of earth from the trench as the wheel rotates. 
When the bucket reaches the top of the wheel, the earth falls onto 
a belt conveyor, which deposits it on the waste bank. The machine 
can be mounted on caterpillar tractors for use in wet soil. It is 
built in several sizes, so that ditches with top widths of from 2 J to 
12 feet and with smooth side slopes can be dug. The cost of the 
excavator varies from $4,000 to $12,000, according to the size of 
ditch it is desired to dig. 
There is a wheel type of trench excavator so designed that by 
adding side knives sloping sides can be dug. This machine is illus- 
trated in Plate VII, figure 2. A series of buckets attached to two 
parallel chains travel over the circumference of a wheel mounted on 
a frame, which is supported by a central shaft about which the wheel 
revolves. The cutting knives slice the earth from the sides of the 
ditch, the dirt falling into the path of the buckets. The excavator 
is made in two sizes. The smaller size will dig 5 feet deep, 90 inches 
wide, and any side slope not natter than 1 to 1. The larger size will 
dig 6 feet deep and 10 feet wide. The machine may be mounted 
on caterpillar tractors. For the small size 4 by 6 foot tractors are 
used, while the large machine requires 4 J by 11 foot tractors. Either 
steam or gasoline power is furnished. This wheel excavator is suit- 
able for the construction of small open ditches. It works to the best 
advantage in a soft, wet soil; under these conditions its average 
daily output is about 300 cubic yards. 
Experience has shown that it is a mistake for a maker to attempt 
to build one machine of this type that is suitable for all classes of 
